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Acharya NK, Grossman HC, Clifford PM, Levin EC, Light KR, Choi H, Swanson Ii RL, Kosciuk MC, Venkataraman V, Libon DJ, Matzel LD, Nagele RG. A Chronic Increase in Blood-Brain Barrier Permeability Facilitates Intraneuronal Deposition of Exogenous Bloodborne Amyloid-Beta1-42 Peptide in the Brain and Leads to Alzheimer's Disease-Relevant Cognitive Changes in a Mouse Model. J Alzheimers Dis 2024; 98:163-186. [PMID: 38393907 DOI: 10.3233/jad-231028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Background Increased blood-brain barrier (BBB) permeability and amyloid-β (Aβ) peptides (especially Aβ1-42) (Aβ42) have been linked to Alzheimer's disease (AD) pathogenesis, but the nature of their involvement in AD-related neuropathological changes leading to cognitive changes remains poorly understood. Objective To test the hypothesis that chronic extravasation of bloodborne Aβ42 peptide and brain-reactive autoantibodies and their entry into the brain parenchyma via a permeable BBB contribute to AD-related pathological changes and cognitive changes in a mouse model. Methods The BBB was rendered chronically permeable through repeated injections of Pertussis toxin (PT), and soluble monomeric, fluorescein isothiocyanate (FITC)-labeled or unlabeled Aβ42 was injected into the tail-vein of 10-month-old male CD1 mice at designated intervals spanning ∼3 months. Acquisition of learned behaviors and long-term retention were assessed via a battery of cognitive and behavioral tests and linked to neuropathological changes. Results Mice injected with both PT and Aβ42 demonstrated a preferential deficit in the capacity for long-term retention and an increased susceptibility to interference in selective attention compared to mice exposed to PT or saline only. Immunohistochemical analyses revealed increased BBB permeability and entry of bloodborne Aβ42 and immunoglobulin G (IgG) into the brain parenchyma, selective neuronal binding of IgG and neuronal accumulation of Aβ42 in animals injected with both PT and Aβ42 compared to controls. Conclusion Results highlight the potential synergistic role of BBB compromise and the influx of bloodborne Aβ42 into the brain in both the initiation and progression of neuropathologic and cognitive changes associated with AD.
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Affiliation(s)
- Nimish K Acharya
- Department of Geriatrics and Gerontology, New Jersey Institute for Successful Aging, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, NJ, USA
- Department of Cell Biology and Neuroscience, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, NJ, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Biomarker Discovery Center, New Jersey Institute for Successful Aging (NJISA), Rowan-Virtua School of Osteopathic Medicine, Stratford, NJ, USA
- Rowan-Virtua Graduate School of Biomedical Sciences, Stratford, NJ, USA
- Rowan-Virtua School of Translational Biomedical Engineering and Sciences, Rowan University, Glassboro, NJ, USA
| | - Henya C Grossman
- Department of Psychology, Rutgers University, Piscataway, NJ, USA
| | - Peter M Clifford
- Department of Geriatrics and Gerontology, New Jersey Institute for Successful Aging, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, NJ, USA
- HNL Lab Medicine, Allentown, PA, USA
| | - Eli C Levin
- Department of Geriatrics and Gerontology, New Jersey Institute for Successful Aging, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, NJ, USA
- Department of Graduate Medical Education, Bayhealth Medical Center, Dover, DE, USA
| | - Kenneth R Light
- Department of Psychology, Barnard College of Columbia University, New York, NY, USA
| | - Hana Choi
- Rowan-Virtua Graduate School of Biomedical Sciences, Stratford, NJ, USA
| | - Randel L Swanson Ii
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Rehab Medicine Service, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Mary C Kosciuk
- Department of Geriatrics and Gerontology, New Jersey Institute for Successful Aging, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, NJ, USA
| | - Venkat Venkataraman
- Department of Cell Biology and Neuroscience, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, NJ, USA
- Department of Academic and Student Affairs, Rowan-Virtua School of Osteopathic Medicine, Stratford, NJ, USA
| | - David J Libon
- Department of Geriatrics and Gerontology, New Jersey Institute for Successful Aging, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, NJ, USA
- Department of Psychology, Rowan University, Glassboro, NJ, USA
| | - Louis D Matzel
- Department of Psychology, Rutgers University, Piscataway, NJ, USA
| | - Robert G Nagele
- Department of Geriatrics and Gerontology, New Jersey Institute for Successful Aging, Rowan-Virtua School of Osteopathic Medicine, Rowan University, Stratford, NJ, USA
- Biomarker Discovery Center, New Jersey Institute for Successful Aging (NJISA), Rowan-Virtua School of Osteopathic Medicine, Stratford, NJ, USA
- Rowan-Virtua Graduate School of Biomedical Sciences, Stratford, NJ, USA
- Rowan-Virtua School of Translational Biomedical Engineering and Sciences, Rowan University, Glassboro, NJ, USA
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Melo de Farias AR, Pelletier A, Iohan LCC, Saha O, Bonnefond A, Amouyel P, Delahaye F, Lambert JC, Costa MR. Amyloid-Beta Peptides Trigger Premature Functional and Gene Expression Alterations in Human-Induced Neurons. Biomedicines 2023; 11:2564. [PMID: 37761004 PMCID: PMC10526858 DOI: 10.3390/biomedicines11092564] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Alzheimer's disease (AD) is the most prevalent cause of dementia in the elderly, characterized by the presence of amyloid-beta (Aβ) plaques, neurofibrillary tangles, neuroinflammation, synapse loss and neurodegeneration in the brain. The amyloid cascade hypothesis postulates that deposition of Aβ peptides is the causative agent of AD pathology, but we still lack comprehensive understanding of the molecular mechanisms connecting Aβ peptides to neuronal dysfunctions in AD. In this work, we investigate the early effects of Aβ peptide accumulation on the functional properties and gene expression profiles of human-induced neurons (hiNs). We show that hiNs acutely exposed to low concentrations of both cell-secreted Aβ peptides or synthetic Aβ1-42 exhibit alterations in the frequency of calcium transients suggestive of increased neuronal excitability. Using single-cell RNA sequencing, we also show that cell-secreted Aβ up-regulates the expression of several synapse-related genes and down-regulates the expression of genes associated with metabolic stress mainly in glutamatergic neurons and, to a lesser degree, in GABAergic neurons and astrocytes. These neuronal alterations correlate with activation of the SEMA5, EPHA and NECTIN signaling pathways, which are important regulators of synaptic plasticity. Altogether, our findings indicate that slight elevations in Aβ concentrations are sufficient to elicit transcriptional changes in human neurons, which can contribute to early alterations in neural network activity.
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Affiliation(s)
- Ana Raquel Melo de Farias
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE Facteurs de Risque et Déterminants Moléculaires des Maladies Liées au Vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019 Lille, France; (A.R.M.d.F.); (O.S.); (P.A.); (J.-C.L.)
- Brain Institute, Federal University of Rio Grande do Norte, Campus Universitário Lagoa Nova, Av. Senador Salgado Filho, 3000, Natal 59078-970, Brazil
| | - Alexandre Pelletier
- Université de Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1283-UMR 8199 EGID, Pôle Recherche, 1 Place de Verdun, CEDEX, 59045 Lille, France; (A.P.); (A.B.); (F.D.)
| | - Lukas Cruz Carvalho Iohan
- Bioinformatics Multidisciplinary Environment, Federal University of Rio Grande do Norte, Natal 59078-970, Brazil;
| | - Orthis Saha
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE Facteurs de Risque et Déterminants Moléculaires des Maladies Liées au Vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019 Lille, France; (A.R.M.d.F.); (O.S.); (P.A.); (J.-C.L.)
| | - Amélie Bonnefond
- Université de Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1283-UMR 8199 EGID, Pôle Recherche, 1 Place de Verdun, CEDEX, 59045 Lille, France; (A.P.); (A.B.); (F.D.)
| | - Philippe Amouyel
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE Facteurs de Risque et Déterminants Moléculaires des Maladies Liées au Vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019 Lille, France; (A.R.M.d.F.); (O.S.); (P.A.); (J.-C.L.)
| | - Fabien Delahaye
- Université de Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1283-UMR 8199 EGID, Pôle Recherche, 1 Place de Verdun, CEDEX, 59045 Lille, France; (A.P.); (A.B.); (F.D.)
| | - Jean-Charles Lambert
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE Facteurs de Risque et Déterminants Moléculaires des Maladies Liées au Vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019 Lille, France; (A.R.M.d.F.); (O.S.); (P.A.); (J.-C.L.)
| | - Marcos R. Costa
- Université de Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE Facteurs de Risque et Déterminants Moléculaires des Maladies Liées au Vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019 Lille, France; (A.R.M.d.F.); (O.S.); (P.A.); (J.-C.L.)
- Brain Institute, Federal University of Rio Grande do Norte, Campus Universitário Lagoa Nova, Av. Senador Salgado Filho, 3000, Natal 59078-970, Brazil
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Frackowiak J, Mazur-Kolecka B. Intraneuronal accumulation of amyloid-β peptides as the pathomechanism linking autism and its co-morbidities: epilepsy and self-injurious behavior - the hypothesis. Front Mol Neurosci 2023; 16:1160967. [PMID: 37305553 PMCID: PMC10250631 DOI: 10.3389/fnmol.2023.1160967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/28/2023] [Indexed: 06/13/2023] Open
Abstract
Autism spectrum disorder (ASD) is associated with enhanced processing of amyloid-β precursor protein (APP) by secretase-α, higher blood levels of sAPPα and intraneuronal accumulation of N-terminally truncated Aβ peptides in the brain cortex - mainly in the GABAergic neurons expressing parvalbumin - and subcortical structures. Brain Aβ accumulation has been also described in epilepsy-the frequent ASD co-morbidity. Furthermore, Aβ peptides have been shown to induce electroconvulsive episodes. Enhanced production and altered processing of APP, as well as accumulation of Aβ in the brain are also frequent consequences of traumatic brain injuries which result from self-injurious behaviors, another ASD co-morbidity. We discuss distinct consequences of accumulation of Aβ in the neurons and synapses depending on the Aβ species, their posttranslational modifications, concentration, level of aggregation and oligomerization, as well as brain structures, cell types and subcellular structures where it occurs. The biological effects of Aβ species which are discussed in the context of the pathomechanisms of ASD, epilepsy, and self-injurious behavior include modulation of transcription-both activation and repression; induction of oxidative stress; activation and alteration of membrane receptors' signaling; formation of calcium channels causing hyper-activation of neurons; reduction of GABAergic signaling - all of which lead to disruption of functions of synapses and neuronal networks. We conclude that ASD, epilepsy, and self-injurious behaviors all contribute to the enhanced production and accumulation of Aβ peptides which in turn cause and enhance dysfunctions of the neuronal networks that manifest as autism clinical symptoms, epilepsy, and self-injurious behaviors.
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Bhuniya S, Goyal M, Chowdhury N, Mishra P. Intermittent hypoxia and sleep disruption in obstructive sleep apnea increase serum tau and amyloid-beta levels. J Sleep Res 2022; 31:e13566. [PMID: 35165967 DOI: 10.1111/jsr.13566] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 01/19/2022] [Accepted: 01/25/2022] [Indexed: 01/16/2023]
Abstract
Obstructive sleep apnea is characterized by intermittent hypoxia and sleep disruption, leading to accelerated neurodegenerative changes and cognitive decline. Serum amyloid-beta and tau proteins, which are markers for Alzheimer's disease, have been reported to increase in patients with obstructive sleep apnea. This study compared the serum levels of amyloid-beta proteins and tau proteins in 46 cognitively normal obstructive sleep apnea patients and 30 healthy controls. Sleep parameters and severity of obstructive sleep apnea were determined using overnight polysomnography. Serum levels of Aβ40, Aβ42, total tau and phosphorylated-tau were determined by enzyme-linked immunosorbent assay. Patients with obstructive sleep apnea had significantly higher median serum levels of Aβ40 (121.0 versus 78.3 pg ml-1 ), Aβ42 (105.6 versus 18.6 pg ml-1 ) and total tau (168.5 versus 10.9 pg ml-1 ) than controls. Serum levels of phosphorylated-tau did not differ significantly between the two groups. Serum levels of amyloid and tau proteins correlated with parameters of nocturnal oxygen saturation. Rapid eye movement sleep was negatively correlated with total amyloid-beta proteins. We conclude that serum levels of amyloid-beta and total tau are higher in patients with obstructive sleep apnea and hypoxia as well as changes in sleep architecture associated with their increased levels. Patients with obstructive sleep apnea should be closely monitored for the signs of cognitive impairment. Obstructive sleep apnea is a modifiable risk factor, and its treatment may reverse neurodegenerative changes and prevent cognitive impairment.
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Affiliation(s)
- Sourin Bhuniya
- Department of Pulmonary Medicine, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
| | - Manish Goyal
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
| | - Nilotpal Chowdhury
- Department of Pathology, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
| | - Priyadarshini Mishra
- Department of Physiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
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Abstract
Chirality is a fundamental feature of asymmetric molecules and of critical importance for intermolecular interactions. The growth of amyloid fibrils displays a strong enantioselectivity, which is manifested as elongation through the addition of monomers of the same, but not opposite, chirality as the parent aggregate. Here we ask whether also secondary nucleation on the surface of amyloid fibrils, of relevance for toxicity, is governed by the chirality of the nucleating monomers. We use short amyloid peptides (Aβ20‐34 and IAPP20‐29) with all residues as L‐ or all D‐enantiomer in self and cross‐seeding experiments with low enough seed concentration that any acceleration of fibril formation is dominated by secondary nucleation. We find a strong enantio‐specificity of this auto‐catalytic process with secondary nucleation being observed in the self‐seeding experiments only. The results highlight a role of secondary nucleation in strain propagation.
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Affiliation(s)
- Mattias Törnquist
- Biochemistry and Structural Biology, Lund University, Kemicentrum, Box 118, 22100, Lund, Sweden
| | - Sara Linse
- Biochemistry and Structural Biology, Lund University, Kemicentrum, Box 118, 22100, Lund, Sweden
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Lee J, Lee K, Lim CT. Surface Plasmon Resonance Assay for Identification of Small Molecules Capable of Inhibiting Aβ Aggregation. ACS Appl Mater Interfaces 2021; 13:27845-27855. [PMID: 34110774 DOI: 10.1021/acsami.1c04833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Toxic aggregates of amyloid-beta (Aβ) have importance in the pathology of Alzheimer's disease, and inhibition of aggregate formation is considered to be a promising strategy for drug development. Here, we report a simple and rapid surface plasmon resonance (SPR) assay method that can identify potential Aβ aggregation inhibitors. Our assay is based on the SPR shifting of the Aβ-gold nanoparticle (Aβ-GNP) aggregates by size under the influence of an Aβ aggregation inhibitor. This user-friendly assay features a short assay time with a low reagent consumption that can be easily adapted as a high-throughput screen. We demonstrated that an effective Aβ aggregation inhibitor induces the blue-shifted SPR peaks of the Aβ-GNP aggregates by hindering the formation of long fibrillar aggregates. Moreover, the blue shifting was correlated to the efficacy and concentrations of an Aβ aggregation inhibitor. Overall, our findings suggest that our simple SPR assay can be a powerful tool to screen small molecules targeting Aβ aggregation.
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Affiliation(s)
- Jeeyeon Lee
- Institute for Health Innovation and Technology (iHealthtech), National University of Singapore, Singapore 117599, Singapore
| | - Kwan Lee
- Department of Advanced Materials Engineering, College of Engineering, Kyungsung University, Busan 48434, Republic of Korea
| | - Chwee Teck Lim
- Institute for Health Innovation and Technology (iHealthtech), National University of Singapore, Singapore 117599, Singapore
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore 117583, Singapore
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Ni R, Röjdner J, Voytenko L, Dyrks T, Thiele A, Marutle A, Nordberg A. In vitro Characterization of the Regional Binding Distribution of Amyloid PET Tracer Florbetaben and the Glia Tracers Deprenyl and PK11195 in Autopsy Alzheimer's Brain Tissue. J Alzheimers Dis 2021; 80:1723-1737. [PMID: 33749648 PMCID: PMC8150513 DOI: 10.3233/jad-201344] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Emerging evidence indicates a central role of gliosis in Alzheimer's disease (AD) pathophysiology. However, the regional distribution and interaction of astrogliosis and microgliosis in association with amyloid-β (Aβ) still remain uncertain. OBJECTIVE Here we studied the pathological profiles in autopsy AD brain by using specific imaging tracers. METHODS Autopsy brain tissues of AD (n = 15, age 70.4±8.5 years) and control cases (n = 12, age 76.6±10.9) were examined with homogenate binding assays, autoradiography for Aβ plaques (3H-florbetaben/3H-PIB), astrogliosis (3H-L-deprenyl), and microgliosis (3H-PK11195/3H-FEMPA), as well as immunoassays. RESULTS In vitro saturation analysis revealed high-affinity binding sites of 3H-florbetaben, 3H-L-deprenyl, and 3H-PK11195/3H-FEMPA in the frontal cortex of AD cases. In vitro3H-florbetaben binding increased across cortical and subcortical regions of AD compared to control with the highest binding in the frontal and parietal cortices. The in vitro3H-L-deprenyl binding showed highest binding in the hippocampus (dentate gyrus) followed by cortical and subcortical regions of AD while the GFAP expression was upregulated only in the hippocampus compared to control. The in vitro3H-PK11195 binding was solely increased in the parietal cortex and the hippocampus of AD compared to control. The 3H-florbetaben binding positively correlated with the 3H-L-deprenyl binding in the hippocampus and parietal cortex of AD and controls. Similarly, a positive correlation was observed between 3H-florbetaben binding and GFAP expression in hippocampus of AD and control. CONCLUSION The use of multi-imaging tracers revealed different regional pattern of changes in autopsy AD brain with respect to amyloid plaque pathology versus astrogliosis and microgliosis.
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Affiliation(s)
- Ruiqing Ni
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Jennie Röjdner
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Larysa Voytenko
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | | | | | - Amelia Marutle
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Agneta Nordberg
- Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Theme Aging, The Aging Brain Unit, Karolinska University Hospital, Stockholm, Sweden
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Chung CW, Kaminski Schierle GS. Intracellular Thermometry at the Micro-/Nanoscale and its Potential Application to Study Protein Aggregation Related to Neurodegenerative Diseases. Chembiochem 2021; 22:1546-1558. [PMID: 33326160 DOI: 10.1002/cbic.202000765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/14/2020] [Indexed: 11/11/2022]
Abstract
Temperature is a fundamental physical parameter that influences biological processes in living cells. Hence, intracellular temperature mapping can be used to derive useful information reflective of thermodynamic properties and cellular behaviour. Herein, existing publications on different thermometry systems, focusing on those that employ fluorescence-based techniques, are reviewed. From developments based on fluorescent proteins and inorganic molecules to metal nanoclusters and fluorescent polymers, the general findings of intracellular measurements from different research groups are discussed. Furthermore, the contradiction of mitochondrial thermogenesis and nuclear-cytoplasmic temperature differences to current thermodynamic understanding are highlighted. Lastly, intracellular thermometry is proposed as a tool to quantify the energy flow and cost associated with amyloid-β42 (Aβ42) aggregation, a hallmark of Alzheimer's disease.
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Affiliation(s)
- Chyi Wei Chung
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Phillipa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Gabriele S Kaminski Schierle
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Phillipa Fawcett Drive, Cambridge, CB3 0AS, UK
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Drabik D, Chodaczek G, Kraszewski S. Effect of Amyloid-β Monomers on Lipid Membrane Mechanical Parameters-Potential Implications for Mechanically Driven Neurodegeneration in Alzheimer's Disease. Int J Mol Sci 2020; 22:E18. [PMID: 33375009 DOI: 10.3390/ijms22010018] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/17/2020] [Accepted: 12/17/2020] [Indexed: 01/21/2023] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disease that results in memory loss and the impairment of cognitive skills. Several mechanisms of AD’s pathogenesis were proposed, such as the progressive accumulation of amyloid-β (Aβ) and τ pathology. Nevertheless, the exact neurodegenerative mechanism of the Aβ remains complex and not fully understood. This paper proposes an alternative hypothesis of the mechanism based on maintaining the neuron membrane’s mechanical balance. The incorporation of Aβ decreases the lipid membrane’s elastic properties, which eventually leads to the impairment of membrane clustering, disruption of mechanical wave propagation, and change in gamma oscillations. The first two disrupt the neuron’s ability to function correctly while the last one decreases sensory encoding and perception enabling. To begin discussing this mechanical-balance hypothesis, we measured the effect of two selected peptides, Aβ-40 and Aβ-42, as well as their fluorescently labeled modification, on membrane mechanical properties. The decrease of bending rigidity, consistent for all investigated peptides, was observed using molecular dynamic studies and experimental flicker-noise techniques. Additionally, wave propagation was investigated with molecular dynamic studies in membranes with and without incorporated neurodegenerative peptides. A change in membrane behavior was observed in the membrane system with incorporated Aβ.
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Harrison JR, Mistry S, Muskett N, Escott-Price V. From Polygenic Scores to Precision Medicine in Alzheimer's Disease: A Systematic Review. J Alzheimers Dis 2020; 74:1271-1283. [PMID: 32250305 PMCID: PMC7242840 DOI: 10.3233/jad-191233] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Late-onset Alzheimer's disease (AD) is highly heritable. The effect of many common genetic variants, single nucleotide polymorphisms (SNPs), confer risk. Variants are clustered in areas of biology, notably immunity and inflammation, cholesterol metabolism, endocytosis, and ubiquitination. Polygenic scores (PRS), which weight the sum of an individual's risk alleles, have been used to draw inferences about the pathological processes underpinning AD. OBJECTIVE This paper aims to systematically review how AD PRS are being used to study a range of outcomes and phenotypes related to neurodegeneration. METHODS We searched the literature from July 2008-July 2018 following PRISMA guidelines. RESULTS 57 studies met criteria. The AD PRS can distinguish AD cases from controls. The ability of AD PRS to predict conversion from mild cognitive impairment (MCI) to AD was less clear. There was strong evidence of association between AD PRS and cognitive impairment. AD PRS were correlated with a number of biological phenotypes associated with AD pathology, such as neuroimaging changes and amyloid and tau measures. Pathway-specific polygenic scores were also associated with AD-related biologically relevant phenotypes. CONCLUSION PRS can predict AD effectively and are associated with cognitive impairment. There is also evidence of association between AD PRS and other phenotypes relevant to neurodegeneration. The associations between pathway specific polygenic scores and phenotypic changes may allow us to define the biology of the disease in individuals and indicate who may benefit from specific treatments. Longitudinal cohort studies are required to test the ability of PGS to delineate pathway-specific disease activity.
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Affiliation(s)
- Judith R. Harrison
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, Cardiff, UK
| | - Sumit Mistry
- MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, Cardiff, UK
| | - Natalie Muskett
- Cardiff University Medical School, University Hospital of Wales, Cardiff, UK
| | - Valentina Escott-Price
- Dementia Research Institute & the MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, Cardiff, UK
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Weber-Adrian D, Kofoed RH, Chan JWY, Silburt J, Noroozian Z, Kügler S, Hynynen K, Aubert I. Strategy to enhance transgene expression in proximity of amyloid plaques in a mouse model of Alzheimer's disease. Theranostics 2019; 9:8127-8137. [PMID: 31754385 PMCID: PMC6857057 DOI: 10.7150/thno.36718] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/29/2019] [Indexed: 12/26/2022] Open
Abstract
Gene therapy can be designed to efficiently counter pathological features characteristic of neurodegenerative disorders. Here, we took advantage of the glial fibrillary acidic protein (GFAP) promoter to preferentially enhance transgene expression near plaques composed of amyloid-beta peptides (Aβ), a hallmark of Alzheimer's disease (AD), in the TgCRND8 mouse model of amyloidosis. Methods: The delivery of intravenously injected recombinant adeno-associated virus mosaic serotype 1/2 (rAAV1/2) to the cortex and hippocampus of TgCRND8 mice was facilitated using transcranial MRI-guided focused ultrasound in combination with microbubbles (MRIgFUS), which transiently and locally increases the permeability of the blood-brain barrier (BBB). rAAV1/2 expression of the reporter green fluorescent protein (GFP) under a GFAP promoter was compared to GFP expression driven by the constitutive human beta actin (HBA) promoter. Results: MRIgFUS targeting the cortex and hippocampus facilitated the entry of rAAV1/2 and GFP expression under the GFAP promoter was localized to GFAP-positive astrocytes. Adjacent to Aβ plaques where GFAP is upregulated, the volume, surface area, and fluorescence intensity of the transgene GFP were greater in rAAV1/2-GFAP-GFP compared to rAAV1/2-HBA-GFP treated animals. In peripheral organs, GFP expression was particularly strong in the liver, irrespective of the promoter. Conclusion: The GFAP promoter enhanced transgene expression in proximity of Aβ plaques in the brain of TgCRND8 mice, and it also resulted in significant expression in the liver. Future gene therapies for neurological disorders could benefit from using a GFAP promoter to regulate transgene expression in response to disease-induced astrocytic reactivity.
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12
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Abstract
Alzheimer’s disease (AD) affects millions of people, however, there is still no effective treatment. The use of focused ultrasound with microbubbles (FUS-MB) for the opening of the blood-brain barrier has been recently studied and may become a promising therapeutic target.
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Affiliation(s)
- Rodrigo Marmo da Costa E Souza
- Neurosurgeon. Departamento de Psicologia, Programa de Neurociências Cognitiva e do Comportamento, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil.,Departamento de Medicina, Liga de Neurologia e Neurocirurgia Funcional da Paraíba, Cabedelo, PB, Brazil
| | - Inaê Carolline Silveira da Silva
- Medical student. Departamento de Medicina, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.,Departamento de Medicina, Liga de Neurologia e Neurocirurgia Funcional da Paraíba, Cabedelo, PB, Brazil
| | - Anna Beatriz Temoteo Delgado
- Medical student. Departamento de Medicina, Faculdade de Ciências Médicas da Paraíba, Cabedelo, PB, Brazil.,Departamento de Medicina, Liga de Neurologia e Neurocirurgia Funcional da Paraíba, Cabedelo, PB, Brazil
| | - Pedro Hugo Vieira da Silva
- Medical student. Departamento de Medicina, Faculdade de Ciências Médicas da Paraíba, Cabedelo, PB, Brazil.,Departamento de Medicina, Liga de Neurologia e Neurocirurgia Funcional da Paraíba, Cabedelo, PB, Brazil
| | - Victor Ribeiro Xavier Costa
- Medical student. Departamento de Medicina, Faculdade de Ciências Médicas da Paraíba, Cabedelo, PB, Brazil.,Departamento de Medicina, Liga de Neurologia e Neurocirurgia Funcional da Paraíba, Cabedelo, PB, Brazil
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13
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Abstract
Mid-life hypertension and cerebral hypoperfusion may be preclinical abnormalities in people who later develop Alzheimer's disease. Although accumulation of amyloid-beta (Aβ) is characteristic of Alzheimer's disease and is associated with upregulation of the vasoconstrictor peptide endothelin-1 within the brain, it is unclear how this affects systemic arterial pressure. We have investigated whether infusion of Aβ40 into ventricular cerebrospinal fluid modulates blood pressure in the Dahl salt-sensitive rat. The Dahl salt-sensitive rat develops hypertension if given a high-salt diet. Intracerebroventricular infusion of Aβ induced a progressive rise in blood pressure in rats with pre-existing hypertension produced by a high-salt diet ( p < 0.0001), but no change in blood pressure in normotensive rats. The elevation in arterial pressure in high-salt rats was associated with an increase in low frequency spectral density in systolic blood pressure, suggesting autonomic imbalance, and reduced cardiac baroreflex gain. Our results demonstrate the potential for intracerebral Aβ to exacerbate hypertension, through modulation of autonomic activity. Present findings raise the possibility that mid-life hypertension in people who subsequently develop Alzheimer's disease may in some cases be a physiological response to reduced cerebral perfusion complicating the accumulation of Aβ within the brain.
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Affiliation(s)
- Hannah M Tayler
- 1 School of Clinical Sciences, University of Bristol, Bristol, UK
| | | | - Taya L Thomas
- 1 School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Patrick G Kehoe
- 1 School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Julian Fr Paton
- 2 School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Seth Love
- 1 School of Clinical Sciences, University of Bristol, Bristol, UK
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14
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Ruiz J, Boehringer R, Grogg M, Raya J, Schirer A, Crucifix C, Hellwig P, Schultz P, Torbeev V. Covalent Tethering and Residues with Bulky Hydrophobic Side Chains Enable Self-Assembly of Distinct Amyloid Structures. Chembiochem 2016; 17:2274-2285. [PMID: 27717158 DOI: 10.1002/cbic.201600440] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Indexed: 11/10/2022]
Abstract
Polymorphism is a common property of amyloid fibers that complicates their detailed structural and functional studies. Here we report experiments illustrating the chemical principles that enable the formation of amyloid polymorphs with distinct stoichiometric composition. Using appropriate covalent tethering we programmed self-assembly of a model peptide corresponding to the [20-41] fragment of human β2-microglobulin into fibers with either trimeric or dimeric amyloid cores. Using a set of biophysical and biochemical methods we demonstrated their distinct structural, morphological, and templating properties. Furthermore, we showed that supramolecular approaches in which the peptide is modified with bulky substituents can also be applied to modulate the formation of different fiber polymorphs. Such strategies, when applied to disease-related peptides and proteins, will greatly help in the evaluation of the biological properties of structurally distinct amyloids.
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Affiliation(s)
- Jérémy Ruiz
- ISIS (Institut de Science et d'Ingénierie Supramoléculaires) and, icFRC (International Center for Frontier Research in Chemistry), University of Strasbourg, CNRS-, UMR 7006, 8 allée Gaspard Monge, 67083, Strasbourg, France
| | - Régis Boehringer
- ISIS (Institut de Science et d'Ingénierie Supramoléculaires) and, icFRC (International Center for Frontier Research in Chemistry), University of Strasbourg, CNRS-, UMR 7006, 8 allée Gaspard Monge, 67083, Strasbourg, France
| | - Marcel Grogg
- ISIS (Institut de Science et d'Ingénierie Supramoléculaires) and, icFRC (International Center for Frontier Research in Chemistry), University of Strasbourg, CNRS-, UMR 7006, 8 allée Gaspard Monge, 67083, Strasbourg, France
| | - Jésus Raya
- Membrane Biophysics and NMR, Institute of Chemistry, University of Strasbourg, CNRS-, UMR 7177, 4 rue Blaise Pascal, 67008, Strasbourg, France
| | - Alicia Schirer
- Laboratory of Bioelectrochemistry and Spectroscopy, University of Strasbourg, CNRS-, UMR 7140, 1 rue Blaise Pascal, 67070, Strasbourg, France
| | - Corinne Crucifix
- Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), INSERM-U964, University of Strasbourg, CNRS-, UMR 7104, 1 rue Laurent Fries, 67404, Illkirch, France
| | - Petra Hellwig
- Laboratory of Bioelectrochemistry and Spectroscopy, University of Strasbourg, CNRS-, UMR 7140, 1 rue Blaise Pascal, 67070, Strasbourg, France
| | - Patrick Schultz
- Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), INSERM-U964, University of Strasbourg, CNRS-, UMR 7104, 1 rue Laurent Fries, 67404, Illkirch, France
| | - Vladimir Torbeev
- ISIS (Institut de Science et d'Ingénierie Supramoléculaires) and, icFRC (International Center for Frontier Research in Chemistry), University of Strasbourg, CNRS-, UMR 7006, 8 allée Gaspard Monge, 67083, Strasbourg, France
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15
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Abstract
An improved understanding of the ways that amyloid-beta peptides are formed could help efforts to find a treatment for Alzheimer's disease.
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Affiliation(s)
- Charles R Sanders
- Department of Biochemistry, Vanderbilt Univeristy, Nashville, United States
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16
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Wezynfeld NE, Stefaniak E, Stachucy K, Drozd A, Płonka D, Drew SC, Krężel A, Bal W. Resistance of Cu(Aβ4-16) to Copper Capture by Metallothionein-3 Supports a Function for the Aβ4-42 Peptide as a Synaptic Cu(II) Scavenger. Angew Chem Int Ed Engl 2016; 55:8235-8. [PMID: 27238224 DOI: 10.1002/anie.201511968] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/23/2015] [Indexed: 01/16/2023]
Abstract
Aβ4-42 is a major species of Aβ peptide in the brains of both healthy individuals and those affected by Alzheimer's disease. It has recently been demonstrated to bind Cu(II) with an affinity approximately 3000 times higher than the commonly studied Aβ1-42 and Aβ1-40 peptides, which are implicated in the pathogenesis of Alzheimer's disease. Metallothionein-3, a protein considered to orchestrate copper and zinc metabolism in the brain and provide antioxidant protection, was shown to extract Cu(II) from Aβ1-40 when acting in its native Zn7 MT-3 form. This reaction is assumed to underlie the neuroprotective effect of Zn7 MT-3 against Aβ toxicity. In this work, we used the truncated model peptides Aβ1-16 and Aβ4-16 to demonstrate that the high-affinity Cu(II) complex of Aβ4-16 is resistant to Zn7 MT-3 reactivity. This indicates that the analogous complex of the full-length peptide Cu(Aβ4-42) will not yield copper to MT-3 in the brain, thus supporting the concept of a physiological role for Aβ4-42 as a Cu(II) scavenger in the synaptic cleft.
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Affiliation(s)
- Nina E Wezynfeld
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Ewelina Stefaniak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Kinga Stachucy
- Laboratory of Chemical Biology, University of Wrocław, Poland
| | - Agnieszka Drozd
- Laboratory of Chemical Biology, University of Wrocław, Poland
| | - Dawid Płonka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland
| | - Simon C Drew
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Australia
| | - Artur Krężel
- Laboratory of Chemical Biology, University of Wrocław, Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
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17
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Matz A, Halamoda-Kenzaoui B, Hamelin R, Mosser S, Alattia JR, Dimitrov M, Moniatte M, Fraering PC. Identification of new Presenilin-1 phosphosites: implication for γ-secretase activity and Aβ production. J Neurochem 2015; 133:409-21. [PMID: 25458374 DOI: 10.1111/jnc.12996] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/02/2014] [Accepted: 11/10/2014] [Indexed: 02/02/2023]
Abstract
An important pathological hallmark of Alzheimer's disease (AD) is the deposition of amyloid-beta (Aβ) peptides in the brain parenchyma, leading to neuronal death and impaired learning and memory. The protease γ-secretase is responsible for the intramembrane proteolysis of the amyloid-β precursor protein (APP), which leads to the production of the toxic Aβ peptides. Thus, an attractive therapeutic strategy to treat AD is the modulation of the γ-secretase activity, to reduce Aβ42 production. Because phosphorylation of proteins is a post-translational modification known to modulate the activity of many different enzymes, we used electrospray (LC-MS/MS) mass spectrometry to identify new phosphosites on highly purified human γ-secretase. We identified 11 new single or double phosphosites in two well-defined domains of Presenilin-1 (PS1), the catalytic subunit of the γ-secretase complex. Next, mutagenesis and biochemical approaches were used to investigate the role of each phosphosite in the maturation and activity of γ-secretase. Together, our results suggest that the newly identified phosphorylation sites in PS1 do not modulate γ-secretase activity and the production of the Alzheimer's Aβ peptides. Individual PS1 phosphosites shall probably not be considered therapeutic targets for reducing cerebral Aβ plaque formation in AD. In this study, we identified 11 new phosphosites in Presenilin-1 (PS1), the catalytic subunit of the Alzheimer's γ-secretase complex. By combining a mutagenesis approach with cell-based and cell-free γ-secretase assays, we demonstrate that the new phosphosites do not modulate the maturation and activity of γ-secretase. Individual PS1 phosphosites shall thus not be considered therapeutic targets for reducing cerebral Aβ plaque formation in Alzheimer's Disease. Aβ, amyloid beta.
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Affiliation(s)
- Alexandre Matz
- Brain Mind Institute and School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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18
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Taniguchi A, Sasaki D, Shiohara A, Iwatsubo T, Tomita T, Sohma Y, Kanai M. Attenuation of the aggregation and neurotoxicity of amyloid-β peptides by catalytic photooxygenation. Angew Chem Int Ed Engl 2013; 53:1382-5. [PMID: 24339209 DOI: 10.1002/anie.201308001] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 10/30/2013] [Indexed: 11/06/2022]
Abstract
Alzheimer's disease (AD), a progressive severe neurodegenerative disorder, is currently incurable, despite intensive efforts worldwide. Herein, we demonstrate that catalytic oxygenation of amyloid-β peptides (Aβ) might be an effective approach to treat AD. Aβ1-42 was oxygenated under physiologically-relevant conditions (pH 7.4, 37 °C) using a riboflavin catalyst and visible light irradiation, with modifications at the Tyr(10) , His(13) , His(14) , and Met(35) residues. The oxygenated Aβ1-42 exhibited considerably lower aggregation potency and neurotoxicity compared with native Aβ. Photooxygenation of Aβ can be performed even in the presence of cells, by using a selective flavin catalyst attached to an Aβ-binding peptide; the Aβ cytotoxicity was attenuated in this case as well. Furthermore, oxygenated Aβ1-42 inhibited the aggregation and cytotoxicity of native Aβ.
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Affiliation(s)
- Atsuhiko Taniguchi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Japan Science and Technology Agency (JST), ERATO, Kanai Life Science Catalysis Project, Bunkyo-ku, Tokyo 113-0033 (Japan)
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19
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Abstract
With as many as 300,000 United States troops in Iraq and Afghanistan having suffered head injuries (Miller, 2012), traumatic brain injury (TBI) has garnered much recent attention. While the cause and severity of these injuries is variable, severe cases can lead to lifelong disability or even death. While aging is the greatest risk factor for Alzheimer's disease (AD), it is now becoming clear that a history of TBI predisposes the individual to AD later in life (Sivanandam and Thakur, 2012). In this review article, we begin by defining hallmark pathological features of AD and the various forms of TBI. Putative mechanisms underlying the risk relationship between these two neurological disorders are then critically considered. Such mechanisms include precipitation and ‘spreading’ of cerebral amyloid pathology and the role of neuroinflammation. The combined problems of TBI and AD represent significant burdens to public health. A thorough, mechanistic understanding of the precise relationship between TBI and AD is of utmost importance in order to illuminate new therapeutic targets. Mechanistic investigations and the development of preclinical therapeutics are reliant upon a clearer understanding of these human diseases and accurate modeling of pathological hallmarks in animal systems.
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Affiliation(s)
- Joshua J Breunig
- Regenerative Medicine Institute, Cedars-Sinai Medical Center Los Angeles, CA, USA ; Department of Biomedical Sciences, Cedars-Sinai Medical Center Los Angeles, CA, USA
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20
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Han X. The pathogenic implication of abnormal interaction between apolipoprotein E isoforms, amyloid-beta peptides, and sulfatides in Alzheimer's disease. Mol Neurobiol 2010; 41:97-106. [PMID: 20052565 PMCID: PMC2877150 DOI: 10.1007/s12035-009-8092-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 12/06/2009] [Indexed: 01/23/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in the aging population. Prior work has shown that the epsilon4 allele of apolipoprotein E (apoE4) is a major risk factor for "sporadic" AD, which accounts for >99% of AD cases without a defined underlying mechanism. Recently, we have demonstrated that sulfatides are substantially and specifically depleted at the very early stage of AD. To identify the mechanism(s) of sulfatide loss concurrent with AD onset, we have found that: (1) sulfatides are specifically associated with apoE-associated particles in cerebrospinal fluid (CSF); (2) apoE modulates cellular sulfatide levels; and (3) the modulation of sulfatide content is apoE isoform dependent. These findings not only lead to identification of the potential mechanisms underlying sulfatide depletion at the earliest stages of AD but also serve as mechanistic links to explain the genetic association of apoE4 with AD. Moreover, our recent studies further demonstrated that (1) apoE mediates sulfatide depletion in amyloid-beta precursor protein transgenic mice; (2) sulfatides enhance amyloid beta (Abeta) peptides binding to apoE-associated particles; (3) Abeta42 content notably correlates with sulfatide content in CSF; (4) sulfatides markedly enhance the uptake of Abeta peptides; and (5) abnormal sulfatide-facilitated Abeta uptake results in the accumulation of Abeta in lysosomes. Collectively, our studies clearly provide a link between apoE, Abeta, and sulfatides in AD and establish a foundation for the development of effective therapeutic interventions for AD.
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Affiliation(s)
- Xianlin Han
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Internal Medicine, Washington University School of Medicine, Campus Box 8020, 660 S. Euclid Avenue, St. Louis, MO 63110, USA,
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21
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Abstract
The major amyloid-beta (Abeta) peptides found in the brain of familial and late onset Alzheimer's disease include the full-length Abeta1-42 and N-terminally truncated, pyroglutamylated peptides Abetap3-42 and Abetap11-42. The biophysical properties of Abeta1-42 have been extensively studied, yet little is known about the other modified peptides. We investigated the aggregation kinetics of brain-specific Abeta peptides to better understand their potential roles in plaque formation. Synthetic peptides were analyzed individually and in mixtures representing various ratios found in the brain. Spectrofluorometric analyses using Thioflavin-T showed that the aggregation of Abeta1-42 was faster compared to Abetap3-42; however, Abetap11-42 displayed similar kinetics. Surprisingly, mixtures of full-length Abeta1-42 and Abetap3-42 showed an initial delay in beta-sheet formation from both equimolar and non-equimolar samples. Electron microscopy of peptides individually and in mixtures further supported fluorescence data. These results indicate that Abeta-Abeta peptide interactions involving different forms may play a critical role in senile plaque formation and maintenance of the soluble Abeta pool in the brain.
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Affiliation(s)
- Hiromi M Sanders
- Department of Physiology, East Carolina University Brody School of Medicine, Greenville, NC 27834, United States.
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