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Croft CL, Futch HS, Moore BD, Golde TE. Organotypic brain slice cultures to model neurodegenerative proteinopathies. Mol Neurodegener 2019; 14:45. [PMID: 31791377 PMCID: PMC6889333 DOI: 10.1186/s13024-019-0346-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/13/2019] [Indexed: 01/30/2023] Open
Abstract
Organotypic slice cultures of brain or spinal cord have been a longstanding tool in neuroscience research but their utility for understanding Alzheimer's disease (AD) and other neurodegenerative proteinopathies has only recently begun to be evaluated. Organotypic brain slice cultures (BSCs) represent a physiologically relevant three-dimensional model of the brain. BSCs support all the central nervous system (CNS) cell types and can be produced from brain areas involved in neurodegenerative disease. BSCs can be used to better understand the induction and significance of proteinopathies underlying the development and progression of AD and other neurodegenerative disorders, and in the future may serve as bridging technologies between cell culture and in vivo experiments for the development and evaluation of novel therapeutic targets and strategies. We review the initial development and general use of BSCs in neuroscience research and highlight the advantages of these cultures as an ex vivo model. Subsequently we focus on i) BSC-based modeling of AD and other neurodegenerative proteinopathies ii) use of BSCs to understand mechanisms underlying these diseases and iii) how BSCs can serve as tools to screen for suitable therapeutics prior to in vivo investigations. Finally, we will examine i) open questions regarding the use of such cultures and ii) how emerging technologies such as recombinant adeno-associated viruses (rAAV) may be combined with these models to advance translational research relevant to neurodegenerative disorders.
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Affiliation(s)
- C L Croft
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - H S Futch
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - B D Moore
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - T E Golde
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA. .,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, 32610, USA. .,McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
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Quan Q, Qian Y, Li X, Li M. Pioglitazone Reduces β Amyloid Levels via Inhibition of PPARγ Phosphorylation in a Neuronal Model of Alzheimer's Disease. Front Aging Neurosci 2019; 11:178. [PMID: 31379559 PMCID: PMC6650543 DOI: 10.3389/fnagi.2019.00178] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/02/2019] [Indexed: 12/28/2022] Open
Abstract
It has been demonstrated that peroxisome proliferator-activated receptor γ (PPARγ) can regulate the transcription of its target gene, insulin-degrading enzyme (IDE), and thus enhance the expression of the IDE protein. The protein can degrade β amyloid (Aβ), a core pathological product of Alzheimer’s disease (AD). PPARγ can also regulate the transcription of other target gene, β-amyloid cleavage enzyme 1 (BACE1), and thus inhibit the expression of the BACE1 protein. BACE1 can hydrolyze amyloid precursor protein (APP), the precursor of Aβ. In adipose tissue, PPARγ agonists can inhibit the phosphorylation of PPARγ by inhibiting cyclin-dependent kinase 5 (CDK5), which in turn affects the expression of target genes regulated by PPARγ. PPARγ agonists may also exert inhibitory effects on the phosphorylation of PPARγ in the brain, thereby affecting the expression of the aforementioned PPARγ target genes and reducing Aβ levels. The present study confirmed this hypothesis by showing that PPARγ agonist pioglitazone attenuated the neuronal apoptosis of primary rat hippocampal neurons induced by Aβ1–42, downregulated CDK5 expression, weakened the binding of CDK5 to PPARγ, reduced PPARγ phosphorylation, increased the expression of PPARγ and IDE, decreased the expression of BACE1, reduced APP production, and downregulated intraneuronal Aβ1–42 levels. These effects were inhibited by the PPARγ antagonist GW9662. After CDK5 silencing with CDK5 shRNA, the above effect of pioglitazone was not observed, except when upregulating the expression of PPARγ in Aβ1–42 treated neurons. In conclusion, this study demonstrated that pioglitazone could inhibit the phosphorylation of PPARγ in vitro by inhibiting CDK5 expression, which in turn affected the expression of PPARγ target genes Ide and Bace1, thereby promoting Aβ degradation and reducing Aβ production. This reduced Aβ levels in the brain, thereby exerting neuroprotective effects in an AD model.
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Affiliation(s)
- Qiankun Quan
- Department of Geriatrics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.,Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Yihua Qian
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education of China, Xi'an Jiaotong University Health Science Center, Xi'an, China
| | - Xi Li
- Department of Geriatrics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Ming Li
- Department of Geriatrics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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Astrocytes and the TGF-β1 Pathway in the Healthy and Diseased Brain: a Double-Edged Sword. Mol Neurobiol 2018; 56:4653-4679. [DOI: 10.1007/s12035-018-1396-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 10/14/2018] [Indexed: 12/14/2022]
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Chong JR, Chai YL, Lee JH, Howlett D, Attems J, Ballard CG, Aarsland D, Francis PT, Chen CP, Lai MKP. Increased Transforming Growth Factor β2 in the Neocortex of Alzheimer's Disease and Dementia with Lewy Bodies is Correlated with Disease Severity and Soluble Aβ42 Load. J Alzheimers Dis 2018; 56:157-166. [PMID: 27911312 DOI: 10.3233/jad-160781] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Of the three transforming growth factor (TGF)-β isoforms known, TGFβ1 deficits have been widely reported in Alzheimer's disease (AD) and studied as a potential therapeutic target. In contrast, the status of TGFβ2, which has been shown to mediate amyloid-β (Aβ)-mediated neuronal death, are unclear both in AD and in Lewy body dementias (LBD) with differential neuritic plaque and neurofibrillary tangle burden. OBJECTIVE To measure neocortical TGFβ2 levels and their correlations with neuropathological and clinical markers of disease severity in a well-characterized cohort of AD as well as two clinical subtypes of LBD, dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), known to manifest relatively high and low Aβ plaque burden, respectively. METHODS Postmortem samples from temporal cortex (BA21) were measured for TGFβ2 using a Luminex-based platform, and correlated with scores for neuritic plaques, neurofibrillary tangles, α-synuclein pathology, dementia severity (as measured by annual decline of Mini-Mental State Examination scores) as well as soluble and total fractions of brain Aβ42. RESULTS TGFβ2 was significantly increased in AD and DLB, but not in PDD. TGFβ2 also correlated with scores for neurofibrillary tangles, Lewy bodies (within the LBD group), dementia severity, and soluble Aβ42 concentration, but not with neuritic plaque scores, total Aβ42, or monomeric α-synuclein immunoreactivity. CONCLUSIONS TGFβ2 is increased in the temporal cortex of AD and DLB, and its correlations with neuropathological and clinical markers of disease severity as well as with soluble Aβ42 load suggest a potential pathogenic role in mediating the neurotoxicity of non-fibrillar Aβ. Our study also indicates the potential utility of targeting TGFβ2 in pharmacotherapeutic approaches to AD and DLB.
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Affiliation(s)
- Joyce R Chong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yuek Ling Chai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jasinda H Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - David Howlett
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - Johannes Attems
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Clive G Ballard
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - Dag Aarsland
- Department of Neurobiology, Ward Sciences and Society, Karolinska Institute, Stockholm, Sweden.,Centre for Age-Related Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Paul T Francis
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - Christopher P Chen
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Mitchell K P Lai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Wolfson Centre for Age-Related Diseases, King's College London, London, UK
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Tapella L, Cerruti M, Biocotino I, Stevano A, Rocchio F, Canonico PL, Grilli M, Genazzani AA, Lim D. TGF-β2 and TGF-β3 from cultured β-amyloid-treated or 3xTg-AD-derived astrocytes may mediate astrocyte-neuron communication. Eur J Neurosci 2018; 47:211-221. [DOI: 10.1111/ejn.13819] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 12/16/2017] [Accepted: 12/18/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Laura Tapella
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
| | - Matteo Cerruti
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
| | - Isabella Biocotino
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
| | - Alessio Stevano
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
| | - Francesca Rocchio
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
| | - Pier Luigi Canonico
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
| | - Mariagrazia Grilli
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
| | - Armando A. Genazzani
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
| | - Dmitry Lim
- Department of Pharmaceutical Sciences; Università degli Studi del Piemonte Orientale “Amedeo Avogadro”; 28100 Novara Italy
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Mitogen-activated protein kinase signaling pathways promote low-density lipoprotein receptor-related protein 1-mediated internalization of beta-amyloid protein in primary cortical neurons. Int J Biochem Cell Biol 2015; 64:252-64. [DOI: 10.1016/j.biocel.2015.04.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/30/2015] [Accepted: 04/21/2015] [Indexed: 01/02/2023]
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Azizi G, Mirshafiey A. The potential role of proinflammatory and antiinflammatory cytokines in Alzheimer disease pathogenesis. Immunopharmacol Immunotoxicol 2012; 34:881-95. [DOI: 10.3109/08923973.2012.705292] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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8
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Jeynes B, Provias J. The case for blood-brain barrier dysfunction in the pathogenesis of Alzheimer's disease. J Neurosci Res 2011; 89:22-8. [PMID: 21046564 DOI: 10.1002/jnr.22527] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease that leads to a progressive loss of integrative and memory capacities of the brain. This is the predominant form of neurodegenerative dementia, with a growing prevalence of between 1 in 50 and 1 in 100 in North America. Numerous hypotheses related to the etiology of AD have developed over the years. However, among the various published hypotheses, the predominant one is related to the progressive and prominent accumulation of central nervous system β-amyloid peptide and the ensuing brain burden created. It is, therefore, important to consider the homeostatic mechanisms underlying β-amyloid transport dynamics between the brain and blood vascular compartments. As well, there is a dynamic interrelationship between soluble and insoluble forms of the peptide. Factors that underlie and regulate these dynamic processes are likely relevant to the end accumulation of β-amyloid peptide in the brain compartment and ultimately in insoluble forms, which is characteristic of, and significant for, the pathophysiology of the Alzheimer's brain. Significantly, and in particular relation to the amyloid burden theory mentioned above, it has been postulated that a dysfunctioning blood-brain barrier (BBB) may play a significant, if not critical, role in the pathogenesis of AD. By allowing the influx of injurious materials or agents into the brain or by impeding or blocking the efflux of those materials and/or agents, BBB-related neuronopathies and their associated sequelae could, and do, ensue.
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Affiliation(s)
- Brian Jeynes
- Faculty of Applied Health Sciences, Brock University, St. Catharine's, Ontario, Canada.
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Provias J, Jeynes B. Immunohistochemical detection of receptor-associated protein in normal human brain and Alzheimer's disease. PATHOLOGY RESEARCH INTERNATIONAL 2011; 2010:173496. [PMID: 21152174 PMCID: PMC2997284 DOI: 10.4061/2010/173496] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 11/04/2009] [Indexed: 11/20/2022]
Abstract
This study is one of the few to characterize immunohistochemically the distribution and localization of Receptor-Associated Protein (RAP) in human autopsy brain. The results show prominent cortical neuronal localization. RAP is clearly identified in large neuronal dendritic/axonal processes. RAP is expressed in both large pyramidal and smaller interneurons. Occasional, much less frequent RAP is detectable in glial cells in white matter, which appear to be predominantly astrocytic. Although RAP is detectable immunohistochemically in Alzheimer's disease autopsy brain, the level of expression appears significantly reduced relative to age-matched control brains. These results suggest, at the immunohistochemical level, that there is a reduction of RAP protein in Alzheimer's disease brain (cortex). In terms of Alzheimer's disease pathophysiology, a reduction of neuronal RAP could then lead to reduced membrane expression of LRP, since RAP has also been shown to be an LRP antagonist.
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Affiliation(s)
- John Provias
- Department of Pathology and Molecular Medicine [Neuropathology], Hamilton Health Sciences, McMaster University, Hamilton, ON, Canada L8L 2X2
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Heparan sulphate proteoglycan and the low-density lipoprotein receptor-related protein 1 constitute major pathways for neuronal amyloid-beta uptake. J Neurosci 2011; 31:1644-51. [PMID: 21289173 DOI: 10.1523/jneurosci.5491-10.2011] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder in which the aggregation and deposition of amyloid-β (Aβ) peptides in the brain are central to its pathogenesis. In healthy brains, Aβ is effectively metabolized with little accumulation. Cellular uptake and subsequent degradation of Aβ is one of the major pathways for its clearance in the brain. Increasing evidence has demonstrated significant roles for the low-density lipoprotein receptor-related protein 1 (LRP1) in the metabolism of Aβ in neurons, glia cells, and along the brain vasculatures. Heparan sulfate proteoglycan (HSPG) has also been implicated in several pathogenic features of AD, including its colocalization with amyloid plaques. Here, we demonstrate that HSPG and LRP1 cooperatively mediate cellular Aβ uptake. Fluorescence-activated cell sorter and confocal microscopy revealed that knockdown of LRP1 suppresses Aβ uptake, whereas overexpression of LRP1 enhances this process in neuronal cells. Heparin, which antagonizes HSPG, significantly inhibited cellular Aβ uptake. Importantly, treatment with heparin or heparinase blocked LRP1-mediated cellular uptake of Aβ. We further showed that HSPG is more important for the binding of Aβ to the cell surface than LRP1. The critical roles of HSPG in cellular Aβ binding and uptake were confirmed in Chinese hamster ovary cells genetically deficient in HSPG. We also showed that heparin and a neutralizing antibody to LRP1 suppressed Aβ uptake in primary neurons. Our findings demonstrate that LRP1 and HSPG function in a cooperative manner to mediate cellular Aβ uptake and define a major pathway through which Aβ gains entry to neuronal cells.
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Dionne KR, Leser JS, Lorenzen KA, Beckham JD, Tyler KL. A brain slice culture model of viral encephalitis reveals an innate CNS cytokine response profile and the therapeutic potential of caspase inhibition. Exp Neurol 2011; 228:222-31. [PMID: 21241693 DOI: 10.1016/j.expneurol.2011.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 12/30/2010] [Accepted: 01/08/2011] [Indexed: 01/04/2023]
Abstract
Viral encephalitis is a significant cause of human morbidity and mortality in large part due to suboptimal diagnosis and treatment. Murine reovirus infection serves as a classic experimental model of viral encephalitis. Infection of neonatal mice with T3 reoviruses results in lethal encephalitis associated with neuronal infection, apoptosis, and CNS tissue injury. We have developed an ex vivo brain slice culture (BSC) system that recapitulates the basic pathological features and kinetics of viral replication seen in vivo. We utilize the BSC model to identify an innate, brain-tissue specific inflammatory cytokine response to reoviral infection, which is characterized by the release of IL6, CXCL10, RANTES, and murine IL8 analog (KC). Additionally, we demonstrate the potential utility of this system as a pharmaceutical screening platform by inhibiting reovirus-induced apoptosis and CNS tissue injury with the pan-caspase inhibitor, Q-VD-OPh. Cultured brain slices not only serve to model events occurring during viral encephalitis, but can also be utilized to investigate aspects of pathogenesis and therapy that are not experimentally accessible in vivo.
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Affiliation(s)
- Kalen R Dionne
- Medical Scientist Training Program, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
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Grovit-Ferbas K, Harris-White ME. Thinking about HIV: the intersection of virus, neuroinflammation and cognitive dysfunction. Immunol Res 2010; 48:40-58. [DOI: 10.1007/s12026-010-8166-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Fuentealba RA, Liu Q, Zhang J, Kanekiyo T, Hu X, Lee JM, LaDu MJ, Bu G. Low-density lipoprotein receptor-related protein 1 (LRP1) mediates neuronal Abeta42 uptake and lysosomal trafficking. PLoS One 2010; 5:e11884. [PMID: 20686698 PMCID: PMC2912373 DOI: 10.1371/journal.pone.0011884] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 07/06/2010] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by the presence of early intraneuronal deposits of amyloid-beta 42 (Abeta42) that precede extracellular amyloid deposition in vulnerable brain regions. It has been hypothesized that endosomal/lysosomal dysfunction might be associated with the pathological accumulation of intracellular Abeta42 in the brain. Our previous findings suggest that the LDL receptor-related protein 1 (LRP1), a major receptor for apolipoprotein E, facilitates intraneuronal Abeta42 accumulation in mouse brain. However, direct evidence of neuronal endocytosis of Abeta42 through LRP1 is lacking. METHODOLOGY/PRINCIPAL FINDINGS Here we show that LRP1 endocytic function is required for neuronal Abeta42 uptake. Overexpression of a functional LRP1 minireceptor, mLRP4, increases Abeta42 uptake and accumulation in neuronal lysosomes. Conversely, knockdown of LRP1 expression significantly decreases neuronal Abeta42 uptake. Disruptions of LRP1 endocytic function by either clathrin knockdown or by removal of its cytoplasmic tail decreased both uptake and accumulation of Abeta42 in neurons. Finally, we show that LRP1-mediated neuronal accumulation of Abeta42 is associated with increased cellular toxicity. CONCLUSIONS/SIGNIFICANCE These results demonstrate that LRP1 endocytic function plays an important role in the uptake and accumulation of Abeta42 in neuronal lysosomes. These findings emphasize the central function of LRP1 in neuronal Abeta metabolism.
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Affiliation(s)
- Rodrigo A. Fuentealba
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Qiang Liu
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Juan Zhang
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Takahisa Kanekiyo
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Xiaoyan Hu
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jin-Moo Lee
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Guojun Bu
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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Schreurs BG. The effects of cholesterol on learning and memory. Neurosci Biobehav Rev 2010; 34:1366-79. [PMID: 20470821 PMCID: PMC2900496 DOI: 10.1016/j.neubiorev.2010.04.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 04/26/2010] [Accepted: 04/28/2010] [Indexed: 02/07/2023]
Abstract
Cholesterol is vital to normal brain function including learning and memory but that involvement is as complex as the synthesis, metabolism and excretion of cholesterol itself. Dietary cholesterol influences learning tasks from water maze to fear conditioning even though cholesterol does not cross the blood brain barrier. Excess cholesterol has many consequences including peripheral pathology that can signal brain via cholesterol metabolites, pro-inflammatory mediators and antioxidant processes. Manipulations of cholesterol within the central nervous system through genetic, pharmacological, or metabolic means circumvent the blood brain barrier and affect learning and memory but often in animals already otherwise compromised. The human literature is no less complex. Cholesterol reduction using statins improves memory in some cases but not others. There is also controversy over statin use to alleviate memory problems in Alzheimer's disease. Correlations of cholesterol and cognitive function are mixed and association studies find some genetic polymorphisms are related to cognitive function but others are not. In sum, the field is in flux with a number of seemingly contradictory results and many complexities. Nevertheless, understanding cholesterol effects on learning and memory is too important to ignore.
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Affiliation(s)
- Bernard G Schreurs
- Blanchette Rockefeller Neurosciences Institute and Department of Physiology and Pharmacology, West Virginia University School of Medicine, BRNI Building, Morgantown, WV 26505-3409-08, USA.
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Cho S, Wood A, Bowlby MR. Brain slices as models for neurodegenerative disease and screening platforms to identify novel therapeutics. Curr Neuropharmacol 2010; 5:19-33. [PMID: 18615151 DOI: 10.2174/157015907780077105] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 12/07/2006] [Accepted: 01/01/2007] [Indexed: 11/22/2022] Open
Abstract
Recent improvements in brain slice technology have made this biological preparation increasingly useful for examining pathophysiology of brain diseases in a tissue context. Brain slices maintain many aspects of in vivo biology, including functional local synaptic circuitry with preserved brain architecture, while allowing good experimental access and precise control of the extracellular environment, making them ideal platforms for dissection of molecular pathways underlying neuronal dysfunction. Importantly, these ex vivo systems permit direct treatment with pharmacological agents modulating these responses and thus provide surrogate therapeutic screening systems without recourse to whole animal studies. Virus or particle mediated transgenic expression can also be accomplished relatively easily to study the function of novel genes in a normal or injured brain tissue context.In this review we will discuss acute brain injury models in organotypic hippocampal and co-culture systems and the effects of pharmacological modulation on neurodegeneration. The review will also cover the evidence of developmental plasticity in these ex vivo models, demonstrating emergence of injury-stimulated neuronal progenitor cells, and neurite sprouting and axonal regeneration following pathway lesioning. Neuro-and axo-genesis are emerging as significant factors contributing to brain repair following many acute and chronic neurodegenerative disorders. Therefore brain slice models may provide a critical contextual experimental system to explore regenerative mechanisms in vitro.
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Affiliation(s)
- Seongeun Cho
- Discovery Neuroscience, Wyeth Research, CN8000, Princeton, NJ 08543, USA.
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Kawata K, Kubota S, Eguchi T, Moritani NH, Shimo T, Kondo S, Nishida T, Minagi S, Takigawa M. Role of the low-density lipoprotein receptor-related protein-1 in regulation of chondrocyte differentiation. J Cell Physiol 2010; 222:138-48. [DOI: 10.1002/jcp.21930] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Amyloid seeds formed by cellular uptake, concentration, and aggregation of the amyloid-beta peptide. Proc Natl Acad Sci U S A 2009; 106:20324-9. [PMID: 19910533 DOI: 10.1073/pnas.0911281106] [Citation(s) in RCA: 317] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the neuropathological hallmarks of Alzheimer's disease (AD) is the amyloid plaque, primarily composed of aggregated amyloid-beta (Abeta) peptide. In vitro, Abeta(1-42), the major alloform of Abeta found in plaques, self-assembles into fibrils at micromolar concentrations and acidic pH. Such conditions do not exist in the extracellular fluid of the brain where the pH is neutral and Abeta concentrations are in the nanomolar range. Here, we show that extracellular soluble Abeta (sAbeta) at concentrations as low as 1 nM was taken up by murine cortical neurons and neuroblastoma (SHSY5Y) cells but not by human embryonic kidney (HEK293) cells. Following uptake, Abeta accumulated in Lysotracker-positive acidic vesicles (likely late endosomes or lysosomes) where effective concentrations (>2.5 microM) were greater than two orders of magnitude higher than that in the extracellular fluid (25 nM), as quantified by fluorescence intensity using laser scanning confocal microscopy. Furthermore, SHSY5Y cells incubated with 1 muM Abeta(1-42) for several days demonstrated a time-dependent increase in intracellular high molecular weight (HMW) (>200 kDa) aggregates, which were absent in cells grown in the presence of Abeta(1-40). Homogenates from these Abeta(1-42)-loaded cells were capable of seeding amyloid fibril growth. These results demonstrate that Abeta can be taken up by certain cells at low physiologically relevant concentrations of extracellular Abeta, and then concentrated into endosomes/lysosomes. At high concentrations, vesicular Abeta aggregates to form HMW species which are capable of seeding amyloid fibril growth. We speculate that extrusion of these aggregates may seed extracellular amyloid plaque formation during AD pathogenesis.
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Cell death and proliferation in acute slices and organotypic cultures of mammalian CNS. Prog Neurobiol 2009; 88:221-45. [DOI: 10.1016/j.pneurobio.2009.01.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 12/09/2008] [Accepted: 01/07/2009] [Indexed: 11/24/2022]
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Abstract
Alzheimer's disease is characterized by the progressive deposition of beta-amyloid (Abeta) within the brain parenchyma and its subsequent accumulation into senile plaques. Pathogenesis of the disease is associated with perturbations in Abeta homeostasis and the inefficient clearance of these soluble and insoluble peptides from the brain. Microglia have been reported to mediate the clearance of fibrillar Abeta (fAbeta) through receptor-mediated phagocytosis; however, their participation in clearance of soluble Abeta peptides (sAbeta) is largely unknown. We report that microglia internalize sAbeta from the extracellular milieu through a nonsaturable, fluid phase macropinocytic mechanism that is distinct from phagocytosis and receptor-mediated endocytosis both in vitro and in vivo. The uptake of sAbeta is dependent on both actin and tubulin dynamics and does not involve clathrin assembly, coated vesicles or membrane cholesterol. Upon internalization, fluorescently labeled sAbeta colocalizes to pinocytic vesicles. Microglia rapidly traffic these soluble peptides into late endolysosomal compartments where they are subject to degradation. Additionally, we demonstrate that the uptake of sAbeta and fAbeta occurs largely through distinct mechanisms and upon internalization are segregated into separate subcellular vesicular compartments. Significantly, we found that upon proteolytic degradation of fluorescently labeled sAbeta, the fluorescent chromophore is retained by the microglial cell. These studies identify an important mechanism through which microglial cells participate in the maintenance of Abeta homeostasis, through their capacity to constitutively clear sAbeta peptides from the brain.
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Eslami P, Johnson MF, Terzakaryan E, Chew C, Harris-White ME. TGF beta2-induced changes in LRP-1/T beta R-V and the impact on lysosomal A beta uptake and neurotoxicity. Brain Res 2008; 1241:176-87. [PMID: 18804458 DOI: 10.1016/j.brainres.2008.08.086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 08/21/2008] [Accepted: 08/25/2008] [Indexed: 01/01/2023]
Abstract
Numerous studies suggest a central role for the low-density lipoprotein receptor-related protein/transforming growth factor beta receptor V in Alzheimer's Disease. We continue our investigation of a ligand for this receptor, transforming growth factor beta2, which is also implicated in Alzheimer Disease pathogenesis, but whose mechanism(s) remain elusive. Confocal imaging reveals that transforming growth factor beta2 rapidly targets amyloid beta peptide to the lysosomal compartment in cortical neurons and induces cell death. Low-density lipoprotein receptor-related protein/transforming growth factor beta receptor V is known as an endocytic receptor, delivering proteins to the lysosomal compartment for degradation. Transforming growth factor beta2 may alter this pathway resulting in increased uptake, intracellular accumulation and toxicity of amyloid beta peptide. RT-PCR and Western blot analysis of transforming growth factor beta2-treated cells demonstrate that transforming growth factor beta2 modestly increases the mRNA and protein levels of low-density lipoprotein receptor-related protein/transforming growth factor beta receptor V as well as increases the uptake activity. Furthermore, transforming growth factor beta2 alters the morphology and numbers of lysosomes in neurons. Lucifer Yellow and lysosomal hydrolase analysis show that transforming growth factor beta2 makes lysosomal membranes unstable and leaky and this effect is exacerbated with the addition of amyloid beta protein. Our data support a key role for low-density lipoprotein receptor-related protein/transforming growth factor beta receptor V in mediating transforming growth factor beta2 enhancement of amyloid beta peptide uptake and neurotoxicity.
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Affiliation(s)
- Pirooz Eslami
- Department of Medicine, University of California, Los Angeles, CA, USA
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Zerbinatti CV, Wahrle SE, Kim H, Cam JA, Bales K, Paul SM, Holtzman DM, Bu G. Apolipoprotein E and low density lipoprotein receptor-related protein facilitate intraneuronal Abeta42 accumulation in amyloid model mice. J Biol Chem 2006; 281:36180-6. [PMID: 17012232 DOI: 10.1074/jbc.m604436200] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The low density lipoprotein receptor-related protein (LRP) is highly expressed in the brain and has been shown to alter the metabolism of amyloid precursor protein and amyloid-beta peptide (Abeta) in vitro. Previously we developed mice that overexpress a functional LRP minireceptor (mLRP2) in their brains and crossed them to the PDAPP mouse model of Alzheimer disease. Overexpression of mLRP2 in 22-month-old PDAPP mice with amyloid plaques increased a pool of carbonate-soluble Abeta in the brain and worsened memory-related behavior. In the current study, we examined the effects of mLRP2 overexpression on 3-month-old PDAPP mice that had not yet developed amyloid plaques. We found significantly higher levels of membrane-associated Abeta42 in the hippocampus of mice that overexpressed mLRP2. Using immunohistochemical methods, we observed significant intraneuronal Abeta42 in the hippocampus and frontal cortex of PDAPP mice, which frequently co-localized with the lysosomal marker LAMP-1. Interestingly, PDAPP mice lacking apolipoprotein E (apoE) had much less intraneuronal Abeta42. We also found that PC12 cells overexpressing mLRP2 cleared Abeta42 and Abeta40 more rapidly from media than PC12 cells transfected with the vector only. Preincubation of apoE3 or apoE4 with Abeta42 increased the rate of Abeta clearance, and this effect was partially blocked by receptor-associated protein. Our results support the hypothesis that LRP binds and endocytoses Abeta42 both directly and via apoE but that endocytosed Abeta42 is not completely degraded and accumulates in intraneuronal lysosomes.
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Affiliation(s)
- Celina V Zerbinatti
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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