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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] [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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Golde TE. Alzheimer’s disease – the journey of a healthy brain into organ failure. Mol Neurodegener 2022; 17:18. [PMID: 35248124 PMCID: PMC8898417 DOI: 10.1186/s13024-022-00523-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/17/2022] [Indexed: 12/19/2022] Open
Abstract
As the most common dementia, Alzheimer’s disease (AD) exacts an immense personal, societal, and economic toll. AD was first described at the neuropathological level in the early 1900s. Today, we have mechanistic insight into select aspects of AD pathogenesis and have the ability to clinically detect and diagnose AD and underlying AD pathologies in living patients. These insights demonstrate that AD is a complex, insidious, degenerative proteinopathy triggered by Aβ aggregate formation. Over time Aβ pathology drives neurofibrillary tangle (NFT) pathology, dysfunction of virtually all cell types in the brain, and ultimately, overt neurodegeneration. Yet, large gaps in our knowledge of AD pathophysiology and huge unmet medical need remain. Though we largely conceptualize AD as a disease of aging, heritable and non-heritable factors impact brain physiology, either continuously or at specific time points during the lifespan, and thereby alter risk for devolvement of AD. Herein, I describe the lifelong journey of a healthy brain from birth to death with AD, while acknowledging the many knowledge gaps that remain regarding our understanding of AD pathogenesis. To ensure the current lexicon surrounding AD changes from inevitable, incurable, and poorly manageable to a lexicon of preventable, curable, and manageable we must address these knowledge gaps, develop therapies that have a bigger impact on clinical symptoms or progression of disease and use these interventions at the appropriate stage of disease.
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Bernardo TC, Marques-Aleixo I, Beleza J, Oliveira PJ, Ascensão A, Magalhães J. Physical Exercise and Brain Mitochondrial Fitness: The Possible Role Against Alzheimer's Disease. Brain Pathol 2016; 26:648-63. [PMID: 27328058 PMCID: PMC8029062 DOI: 10.1111/bpa.12403] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/15/2016] [Indexed: 12/21/2022] Open
Abstract
Exercise is one of the most effective strategies to maintain a healthy body and mind, with particular beneficial effects of exercise on promoting brain plasticity, increasing cognition and reducing the risk of cognitive decline and dementia in later life. Moreover, the beneficial effects resulting from increased physical activity occur at different levels of cellular organization, mitochondria being preferential target organelles. The relevance of this review article relies on the need to integrate the current knowledge of proposed mechanisms, focus mitochondria, to explain the protective effects of exercise that might underlie neuroplasticity and seeks to synthesize these data in the context of exploring exercise as a feasible intervention to delay cognitive impairment associated with neurodegenerative conditions, particularly Alzheimer disease.
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Affiliation(s)
- T C Bernardo
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal.
| | - I Marques-Aleixo
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
| | - J Beleza
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
| | - P J Oliveira
- CNC-Centre for Neuroscience and Cell Biology, UC-Biotech, Biocant Park, University of Coimbra, Coimbra, Portugal
| | - A Ascensão
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
| | - J Magalhães
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
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Atamna H, Brahmbhatt M, Atamna W, Shanower GA, Dhahbi JM. ApoHRP-based assay to measure intracellular regulatory heme. Metallomics 2015; 7:309-21. [PMID: 25525887 DOI: 10.1039/c4mt00246f] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The majority of the heme-binding proteins possess a "heme-pocket" that stably binds to heme. Usually known as housekeeping heme-proteins, they participate in a variety of metabolic reactions (e.g., catalase). Heme also binds with lower affinity to the "Heme-Regulatory Motifs" (HRM) in specific regulatory proteins. This type of heme binding is known as exchangeable or regulatory heme (RH). Heme binding to HRM proteins regulates their function (e.g., Bach1). Although there are well-established methods for assaying total cellular heme (e.g., heme-proteins plus RH), currently there is no method available for measuring RH independent of the total heme (TH). The current study describes and validates a new method to measure intracellular RH. This method is based on the reconstitution of apo-horseradish peroxidase (apoHRP) with heme to form holoHRP. The resulting holoHRP activity is then measured with a colorimetric substrate. The results show that apoHRP specifically binds RH but not with heme from housekeeping heme-proteins. The RH assay detects intracellular RH. Furthermore, using conditions that create positive (hemin) or negative (N-methyl protoporphyrin IX) controls for heme in normal human fibroblasts (IMR90), the RH assay shows that RH is dynamic and independent of TH. We also demonstrated that short-term exposure to subcytotoxic concentrations of lead (Pb), mercury (Hg), or amyloid-β (Aβ) significantly alters intracellular RH with little effect on TH. In conclusion the RH assay is an effective assay to investigate intracellular RH concentration and demonstrates that RH represents ∼6% of total heme in IMR90 cells.
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Affiliation(s)
- Hani Atamna
- Department of Basic Sciences, TCMC, Scranton, PA, USA
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Bu XL, Rao PPN, Wang YJ. Anti-amyloid Aggregation Activity of Natural Compounds: Implications for Alzheimer's Drug Discovery. Mol Neurobiol 2015; 53:3565-3575. [PMID: 26099310 DOI: 10.1007/s12035-015-9301-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/09/2015] [Indexed: 11/24/2022]
Abstract
Several plant-derived natural compounds are known to exhibit anti-amyloid aggregation activity which makes them attractive as potential therapies to treat Alzheimer's disease. The mechanisms of their anti-amyloid activity are not well known. In this regard, many natural compounds are known to exhibit direct binding to various amyloid species including oligomers and fibrils, which in turn can lead to conformational change in the beta-sheet assembly to form nontoxic aggregates. This review discusses the mechanism of anti-amyloid activity of 16 natural compounds and gives structural details on their direct binding interactions with amyloid aggregates. Our computational investigations show that the physicochemical properties of natural products do fit Lipinski's criteria and that catechol and catechol-type moieties present in natural compounds act as lysine site-specific inhibitors of amyloid aggregation. Based on these observations, we propose a structural template to design novel small molecules containing site-specific ring scaffolds, planar aromatic and nonaromatic linkers with suitably substituted hydrogen bond acceptors and donors. These studies will have significant implications in the design and development of novel amyloid aggregation inhibitors with superior metabolic stability and blood-brain barrier penetration as potential agents to treat Alzheimer's disease.
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Affiliation(s)
- Xian-Le Bu
- Department of Neurology and Center for Clinical Neuroscience, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, China
| | - Praveen P N Rao
- School of Pharmacy, Health Sciences Campus, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
| | - Yan-Jiang Wang
- Department of Neurology and Center for Clinical Neuroscience, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, China.
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Kam TI, Song S, Gwon Y, Park H, Yan JJ, Im I, Choi JW, Choi TY, Kim J, Song DK, Takai T, Kim YC, Kim KS, Choi SY, Choi S, Klein WL, Yuan J, Jung YK. FcγRIIb mediates amyloid-β neurotoxicity and memory impairment in Alzheimer's disease. J Clin Invest 2013; 123:2791-802. [PMID: 23921129 DOI: 10.1172/jci66827] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 04/11/2013] [Indexed: 01/12/2023] Open
Abstract
Amyloid-β (Aβ) induces neuronal loss and cognitive deficits and is believed to be a prominent cause of Alzheimer's disease (AD); however, the cellular pathology of the disease is not fully understood. Here, we report that IgG Fcγ receptor II-b (FcγRIIb) mediates Aβ neurotoxicity and neurodegeneration. We found that FcγRIIb is significantly upregulated in the hippocampus of AD brains and neuronal cells exposed to synthetic Aβ. Neuronal FcγRIIb activated ER stress and caspase-12, and Fcgr2b KO primary neurons were resistant to synthetic Aβ-induced cell death in vitro. Fcgr2b deficiency ameliorated Aβ-induced inhibition of long-term potentiation and inhibited the reduction of synaptic density by naturally secreted Aβ. Moreover, genetic depletion of Fcgr2b rescued memory impairments in an AD mouse model. To determine the mechanism of action of FcγRIIb in Aβ neurotoxicity, we demonstrated that soluble Aβ oligomers interact with FcγRIIb in vitro and in AD brains, and that inhibition of their interaction blocks synthetic Aβ neurotoxicity. We conclude that FcγRIIb has an aberrant, but essential, role in Aβ-mediated neuronal dysfunction.
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Affiliation(s)
- Tae-In Kam
- Global Research Laboratory, School of Biological Sciences/Bio-Max Institute, Seoul National University, Seoul, Republic of Korea
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7
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Youmans KL, Tai LM, Kanekiyo T, Stine WB, Michon SC, Nwabuisi-Heath E, Manelli AM, Fu Y, Riordan S, Eimer WA, Binder L, Bu G, Yu C, Hartley DM, LaDu MJ. Intraneuronal Aβ detection in 5xFAD mice by a new Aβ-specific antibody. Mol Neurodegener 2012; 7:8. [PMID: 22423893 PMCID: PMC3355009 DOI: 10.1186/1750-1326-7-8] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 03/16/2012] [Indexed: 02/07/2023] Open
Abstract
Background The form(s) of amyloid-β peptide (Aβ) associated with the pathology characteristic of Alzheimer's disease (AD) remains unclear. In particular, the neurotoxicity of intraneuronal Aβ accumulation is an issue of considerable controversy; even the existence of Aβ deposits within neurons has recently been challenged by Winton and co-workers. These authors purport that it is actually intraneuronal APP that is being detected by antibodies thought to be specific for Aβ. To further address this issue, an anti-Aβ antibody was developed (MOAB-2) that specifically detects Aβ, but not APP. This antibody allows for the further evaluation of the early accumulation of intraneuronal Aβ in transgenic mice with increased levels of human Aβ in 5xFAD and 3xTg mice. Results MOAB-2 (mouse IgG2b) is a pan-specific, high-titer antibody to Aβ residues 1-4 as demonstrated by biochemical and immunohistochemical analyses (IHC), particularly compared to 6E10 (a commonly used commercial antibody to Aβ residues 3-8). MOAB-2 did not detect APP or APP-CTFs in cell culture media/lysates (HEK-APPSwe or HEK-APPSwe/BACE1) or in brain homogenates from transgenic mice expressing 5 familial AD (FAD) mutation (5xFAD mice). Using IHC on 5xFAD brain tissue, MOAB-2 immunoreactivity co-localized with C-terminal antibodies specific for Aβ40 and Aβ42. MOAB-2 did not co-localize with either N- or C-terminal antibodies to APP. In addition, no MOAB-2-immunreactivity was observed in the brains of 5xFAD/BACE-/- mice, although significant amounts of APP were detected by N- and C-terminal antibodies to APP, as well as by 6E10. In both 5xFAD and 3xTg mouse brain tissue, MOAB-2 co-localized with cathepsin-D, a marker for acidic organelles, further evidence for intraneuronal Aβ, distinct from Aβ associated with the cell membrane. MOAB-2 demonstrated strong intraneuronal and extra-cellular immunoreactivity in 5xFAD and 3xTg mouse brain tissues. Conclusions Both intraneuronal Aβ accumulation and extracellular Aβ deposition was demonstrated in 5xFAD mice and 3xTg mice with MOAB-2, an antibody that will help differentiate intracellular Aβ from APP. However, further investigation is required to determine whether a molecular mechanism links the presence of intraneuronal Aβ with neurotoxicity. As well, understanding the relevance of these observations to human AD patients is critical.
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Affiliation(s)
- Katherine L Youmans
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, IL 60612, USA
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8
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Intraneuronal APP, not free Aβ peptides in 3xTg-AD mice: implications for tau versus Aβ-mediated Alzheimer neurodegeneration. J Neurosci 2011; 31:7691-9. [PMID: 21613482 DOI: 10.1523/jneurosci.6637-10.2011] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of intraneuronal tau and extracellular amyloid-β (Aβ) peptide. A triple transgenic (Tg) mouse (3xTg-AD) was reported to develop Aβ plaques and tau inclusions as well as remarkable accumulations of intracellular Aβ that were suggested to be the initiators of AD pathogenesis. However, it was unclear whether the anti-Aβ antibodies were able to distinguish Aβ peptide from the same Aβ epitopes within the amyloid precursor protein (APP). To further elucidate the identity of the immunoreactive intraneuronal material in 3xTg-AD mice, we conducted immunohistochemical, biochemical, and ultrastructural studies using a well characterized panel of antibodies that distinguish Aβ within APP from cleaved Aβ peptides. We found that the intraneuronal material shared epitopes with full-length APP but not free Aβ. To demonstrate unequivocally that this intraneuronal material was not free Aβ peptide, we generated 3xTg-AD mice deficient for β-secretase (BACE), the protease required for Aβ generation from APP. In the absence of Aβ production, robust intraneuronal APP immunostaining was detected in the 3xTg-AD/BACE(-/-) mice. Finally, we found that the formation of tau lesions was not different between 3xTg-AD versus 3xTg-AD/BACE(-/-) mice, thereby demonstrating that tau pathology forms independently from Aβ peptide generation in this mouse model. Although we cannot corroborate the presence of intraneuronal Aβ peptide in 3xTg-AD mice, our findings warrant further study as to the role of aberrant APP accumulation in this unique model of AD.
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Reddy PH. Abnormal tau, mitochondrial dysfunction, impaired axonal transport of mitochondria, and synaptic deprivation in Alzheimer's disease. Brain Res 2011; 1415:136-48. [PMID: 21872849 DOI: 10.1016/j.brainres.2011.07.052] [Citation(s) in RCA: 199] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 07/20/2011] [Accepted: 07/26/2011] [Indexed: 01/01/2023]
Abstract
Growing evidence suggests that amyloid beta (Aβ) and tau pathologies are strongly associated with mitochondrial dysfunction and neuronal damage in Alzheimer's disease (AD). Extensive research of AD postmortem brains, mouse and fly models, including triple transgenic AD mice and mutant tau mice, and cell culture studies revealed that tau hyperphosphorylation is caused by multiple factors, including intraneuronal Aβ-oligomers, chronic oxidative stress, reduced insulin-like growth factor 1, and astrocytic mediated-Aβ and caspase activation. Overexpressed and phosphorylated tau appears to impair axonal transport of organelles causing synapse starvation, depletion of ATP, and ultimately neuronal damage. This article evaluates the role of tau in mitochondrial dysfunction and assesses how hyperphosphorylated tau impairs axonal transport of organelles in AD neurons.
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Affiliation(s)
- P Hemachandra Reddy
- Neurogenetics Laboratory, Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185th Avenue, Beaverton, OR 97006, USA.
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Kumar R, Atamna H. Therapeutic approaches to delay the onset of Alzheimer's disease. J Aging Res 2011; 2011:820903. [PMID: 21423548 PMCID: PMC3056246 DOI: 10.4061/2011/820903] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 01/10/2011] [Indexed: 12/15/2022] Open
Abstract
The key cytopathologies in the brains of Alzheimer's disease (AD) patients include mitochondrial dysfunction and energy hypometabolism, which are likely caused by the accumulation of small aggregates of amyloid-β (Aβ) peptides. Thus, targeting these two abnormalities of the AD brain may hold promising therapeutic value for delaying the onset of AD. In his paper, we discuss two potential approaches to delay the onset of AD. The first is the use of low dose of diaminophenothiazins (redox active agents) to prevent mitochondrial dysfunction and to attenuate energy hypometabolism. Diaminophenothiazines enhance mitochondrial metabolic activity and heme synthesis, both key factors in intermediary metabolism of the AD brain.The second is to use the naturally occurring osmolytes to prevent the formation of toxic forms of Aβ and prevent oxidative stress. Scientific evidence suggests that both approaches may change course of the basic mechanism of neurodegeneration in AD. Osmolytes are brain metabolites which accumulate in tissues at relatively high concentrations following stress conditions. Osmolytes enhance thermodynamic stability of proteins by stabilizing natively-folded protein conformation, thus preventing aggregation without perturbing other cellular processes. Osmolytes may inhibit the formation of Aβ oligomers in vivo, thus preventing the formation of soluble oligomers. The potential significance of combining diaminophenothiazins and osmolytes to treat AD is discussed.
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Affiliation(s)
- Raj Kumar
- Department of Basic Sciences, Neuroscience, The Commonwealth Medical College, Tobin Hall, 501 Madison Avenue, Scranton, PA 18510, USA
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Troy CM, Akpan N, Jean YY. Regulation of Caspases in the Nervous System. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 99:265-305. [DOI: 10.1016/b978-0-12-385504-6.00007-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Anekonda TS, Quinn JF, Harris C, Frahler K, Wadsworth TL, Woltjer RL. L-type voltage-gated calcium channel blockade with isradipine as a therapeutic strategy for Alzheimer's disease. Neurobiol Dis 2011; 41:62-70. [PMID: 20816785 PMCID: PMC2982927 DOI: 10.1016/j.nbd.2010.08.020] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 08/18/2010] [Accepted: 08/25/2010] [Indexed: 12/31/2022] Open
Abstract
There is strong evidence that intracellular calcium dysregulation plays an important pathological role in Alzheimer's disease, and specifically that beta amyloid may induce increases in intracellular calcium and lead to neuronal cell dysfunction and death. Here we investigated the feasibility of modifying Alzheimer's pathology with the L-type voltage-gated calcium channel blockers verapamil, diltiazem, isradipine and nimodipine. All four compounds protected MC65 neuroblastoma cells from amyloid beta protein precursor C-terminal fragment (APP CTF)-induced neurotoxicity. Isradipine was the most potent blocker, preventing APP CTF neurotoxicity at nanomolar concentrations. Intracellular beta amyloid expression was associated with increased expression of Cav 1.2 calcium channels and increased intracellular calcium influx from the extracellular space. Despite the cytoprotection afforded by calcium channel blockers, amyloid beta oligomer formation was not suppressed. The mechanism of cell death in MC65 cells is appeared to be caspase-3 independent. With the goal of determining if there is sufficient experimental support to move forward with animal trials of isradipine, we determined its bioavailability in the triple transgenic mouse model of AD. Subcutaneous implantation of carrier-bound isradipine (3 μg/g/day) for 60 days resulted in nanomolar concentrations in both the plasma and brain. Taken together, our in vitro results support the theory that calcium blockers exert protective effects downstream of the effects of beta amyloid. Isradipine's neuroprotective effect at concentrations that are clinically relevant and achievable in vitro and in vivo suggests that this particular calcium blocking agent may have therapeutic value in the treatment of Alzheimer's disease.
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Affiliation(s)
- Thimmappa S Anekonda
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA.
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Alkadhi KA, Srivareerat M, Tran TT. Intensification of long-term memory deficit by chronic stress and prevention by nicotine in a rat model of Alzheimer's disease. Mol Cell Neurosci 2010; 45:289-96. [PMID: 20624465 DOI: 10.1016/j.mcn.2010.06.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Revised: 06/24/2010] [Accepted: 06/28/2010] [Indexed: 12/28/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cholinergic dysfunction and deposition of beta-amyloid (Aβ) in regions of the brain associated with learning and memory. The sporadic nature and late onset of most AD cases suggests that aside from biological determinants, environmental factors such as stress may also play a role in the progression of the disease. Behavioral and molecular studies were utilized to evaluate the effects of chronic nicotine treatment in the prevention of impairment of long-term memory. The rat model of AD was induced by i.c.v. osmotic pump infusion of Aβ peptides. Chronic psychosocial stress and chronic nicotine treatment were instituted for 6weeks. Spatial memory testing in the Radial Arm Water Maze revealed that, although stress, by itself, did not affect long-term memory, the combination of chronic stress and Aβ infusion impaired long-term memory significantly more than Aβ peptides infusion alone. Chronic nicotine treatment completely prevented Aβ- and stress/Aβ combination-induced memory impairment. Furthermore, molecular findings in hippocampal CA1 region of stress/Aβ rats indicated marked reduction in the protein levels of phosphorylated cAMP response element binding (p-CREB) and calcium-calmodulin-dependent protein kinase IV (CaMKIV), with significant increases in the levels of brain-derived neurotrophic factor (BDNF). These disturbances in signaling pathways, which may be the underlying mechanisms of impairment of long-term memory in these rats, were totally prevented by chronic nicotine treatment.
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Affiliation(s)
- Karim A Alkadhi
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204-5037, USA.
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Amino acids variations in Amyloid-β peptides, mitochondrial dysfunction, and new therapies for Alzheimer’s disease. J Bioenerg Biomembr 2009; 41:457-64. [DOI: 10.1007/s10863-009-9246-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Atamna H, Frey WH, Ko N. Human and rodent amyloid-beta peptides differentially bind heme: relevance to the human susceptibility to Alzheimer's disease. Arch Biochem Biophys 2009; 487:59-65. [PMID: 19454279 DOI: 10.1016/j.abb.2009.05.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 05/12/2009] [Indexed: 11/30/2022]
Abstract
Amyloid-beta (Abeta) peptides are implicated in the neurodegeneration of Alzheimer's disease (AD). We previously investigated the mechanism of neurotoxicity of Abeta and found that human Abeta (huAbeta) binds and depletes heme, forming an Abeta-heme complex with peroxidase activity. Rodent Abeta (roAbeta) is identical to huAbeta, except for three amino acids within the proposed heme-binding motif (Site-H). We studied and compared heme-binding between roAbeta and huAbeta. Unlike roAbeta, huAbeta binds heme tightly (K(d)=140+/-60 nM) and forms a peroxidase. The plot of bound (huAbeta-heme) vs. unbound heme fits best to a two site binding hyperbola, suggesting huAbeta possesses two heme-binding sites. Consistently, a second high affinity heme-binding site was identified in the lipophilic region (site-L) of huAbeta (K(d)=210+/-80 nM). The plot of (roAbeta-heme) vs. unbound heme, on the other hand, was different as it fits best to a sigmoidal binding curve, indicating different binding and lower affinity of roAbeta for heme (K(d)=1 microM). The effect of heme-binding to site-H on heme-binding to site-L in roAbeta and huAbeta is discussed. While both roAbeta and huAbeta form aggregates equally, rodents lack AD-like neuropathology. High huAbeta/heme ratio increases the peroxidase activity. These findings suggest that depletion of regulatory heme and formation of Abeta-heme peroxidase contribute to huAbeta's neurotoxicity in the early stages of AD. Phylogenic variations in the amino acid sequence of Abeta explain tight heme-binding to huAbeta and likely contribute to the increased human susceptibility to AD.
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Affiliation(s)
- Hani Atamna
- Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA.
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RIBE EM, SERRANO-SAIZ E, AKPAN N, TROY CM. Mechanisms of neuronal death in disease: defining the models and the players. Biochem J 2008; 415:165-82. [PMID: 18800967 PMCID: PMC9334905 DOI: 10.1042/bj20081118] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
Dysregulation of life and death at the cellular level leads to a variety of diseases. In the nervous system, aberrant neuronal death is an outstanding feature of neurodegenerative diseases. Since the discovery of the caspase family of proteases, much effort has been made to determine how caspases function in disease, including neurodegenerative diseases. Although many papers have been published examining caspases in neuronal death and disease, the pathways have not been fully clarified. In the present review, we examine the potential players in the death pathways, the current tools for examining these players and the models for studying neurological disease. Alzheimer's disease, the most common neurodegenerative disorder, and cerebral ischaemia, the most common cause of neurological death, are used to illustrate our current understanding of death signalling in neurodegenerative diseases. A better understanding of the neuronal death pathways would provide targets for the development of therapeutic interventions for these diseases.
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Affiliation(s)
- Elena M. RIBE
- Departments of Pathology and Neurology, Taub Center for the Study of Alzheimer’s Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, 630 W. 168th Street, New York, NY 10032, U.S.A
| | - Esther SERRANO-SAIZ
- Departments of Pathology and Neurology, Taub Center for the Study of Alzheimer’s Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, 630 W. 168th Street, New York, NY 10032, U.S.A
| | - Nsikan AKPAN
- Departments of Pathology and Neurology, Taub Center for the Study of Alzheimer’s Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, 630 W. 168th Street, New York, NY 10032, U.S.A
| | - Carol M. TROY
- Departments of Pathology and Neurology, Taub Center for the Study of Alzheimer’s Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, 630 W. 168th Street, New York, NY 10032, U.S.A
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Arvanitis DN, Ducatenzeiler A, Ou JN, Grodstein E, Andrews SD, Tendulkar SR, Ribeiro-da-Silva A, Szyf M, Cuello AC. High intracellular concentrations of amyloid-beta block nuclear translocation of phosphorylated CREB. J Neurochem 2007; 103:216-28. [PMID: 17587310 DOI: 10.1111/j.1471-4159.2007.04704.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The beta-amyloid peptide (Abeta) is considered responsible for the pathogenesis of Alzheimer's disease. Despite the magnitude of reports describing a neurotoxic role of extracellular Abeta, the role for intracellular Abeta (iAbeta) has not been elucidated. We previously demonstrated that in rat pheochromocytoma cells expression of moderate levels of Abeta results in the up-regulation of phospho-extracellular signal-regulated kinases (ERK1)/2 along with an elevation of cyclic AMP-response element (CRE)-regulated gene expression; however, the effect of high intracellular levels of Abeta were not examined. Towards this goal we generated constructs that endogenously produce different expression levels of iAbeta in a human cell line. We show a bimodal response to Abeta in a neural human cell line. A moderate increase of endogenous Abeta up-regulates certain cyclic AMP-response element-binding protein (CREB) responsive genes such as presenilin 1, presenilin 2, brain-derived neurotrophic factor, and mRNA and protein levels by CREB activation and Synapsin 1 nuclear translocation. On the other hand, high-loads of iAbeta resulted in sustained hyper-phosphorylation of CREB that did not translocate to the nucleus and did not stimulate activation of CRE-regulated gene expression. Our study suggests that variations in levels of iAbeta could influence signaling mechanisms that lead to phosphorylation of CREB, its nuclear translocation and CRE-regulated genes involved in production of Abeta and synaptic plasticity in opposite directions.
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Affiliation(s)
- D N Arvanitis
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada
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Blanchard J, Martel G, Guillou JL, Noguès X, Micheau J. Impairment of spatial memory consolidation in APP(751SL) mice results in cue-guided response. Neurobiol Aging 2007; 29:1011-21. [PMID: 17350733 DOI: 10.1016/j.neurobiolaging.2007.02.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 01/08/2007] [Accepted: 02/05/2007] [Indexed: 11/16/2022]
Abstract
APP(751SL) mice of 5-6- and 7-8-month-old and their wild-type littermates were submitted to one-session learning in a water-maze with three levels of training (4, 12 or 22 trials). Training consisted in finding a submerged platform with a fixed location and marked by a cue. During testing two platforms were presented: one consistent with the spatial location allowing place-response (PR) and the other signaled by the cue enabling cued-response (CR). When testing occurred 24h after training, wild-type and 5-6-month-old APP(751SL) mice exhibited a shift in response strategy as a function of training level, by executing CR when trained with 4 trials and PR when trained with 12 trials, but 7-8-month-old APP(751SL) mice executed only CR. However, they displayed PR when tested 1h after 12- and 22-trial, suggesting a consolidation deficit. Zif268 imaging showed plasticity impairment of the hippocampal-dependent memory system but not of the dorsolateral caudate nucleus. Moreover, in these APP(751SL) mice, the deficit selectively affecting hippocampal function cannot be directly related to the onset of beta-amyloid deposits.
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Affiliation(s)
- J Blanchard
- Laboratory of Cognitive Neuroscience, CNRS UMR 5106, University of Bordeaux I, Avenue des Facultés, 33405 Talence Cedex, France
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