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Yang C, Zheng C, Zhuang Y, Xu S, Li J, Hu C. Synaptic Vesicle-Related Proteins and Ubiquilin 2 in Cortical Synaptosomes Mediate Cognitive Impairment in Vascular Dementia Rats. Mol Neurobiol 2024:10.1007/s12035-024-04327-w. [PMID: 38990251 DOI: 10.1007/s12035-024-04327-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 06/21/2024] [Indexed: 07/12/2024]
Abstract
Synaptic dysfunction is considered the best neuropathological correlate of cognitive decline in vascular dementia (VaD). However, the alterations of synaptic proteins at the synaptosomal level in VaD remain unclear. In this study, a VaD model was established in male rats using bilateral common carotid artery occlusion (2VO). We performed a novel object recognition task to evaluate cognitive impairment. Immunohistochemistry was used to assess the expression of neuron-specific nuclear binding protein (NeuN). Brain synaptosomes were isolated and subjected to label-free proteomic analysis to quantify and identify the synaptic features of differentially expressed proteins (DEPs). Synaptic and hub protein expression was detected in synaptosomes using western blotting. We found that male rats with VaD presented impaired memory and decreased NeuN protein expression in the cortex. Synaptosome proteomic analysis revealed 604 DEPs, with 493 and 111 markedly downregulated and upregulated proteins, respectively. KEGG analysis and SynGO annotation revealed that the synaptic vesicle (SV) cycle may be a key signaling pathway in VaD. Hub protein analysis of the main nodes in the protein network identified UBQLN2 and SV-related proteins, including CLTC, SNAP91, AP2S1, CLTA, VAMP2, EPN1, UBQLN2, AP2B1, AP2A2, and AP2M1. Western blotting showed that the levels of SV2A, CLTC, AP2S1, and VAMP2 decreased in the synaptosomes of 2VO rats, while UBQLN2 expression significantly increased. Our results suggest that the disruption in the presynaptic SV cycle is a key event in male rats with VaD, which could be characterized by the aberrant SV2A expression. SV-related proteins and UBQLN2 may be essential in synaptopathy. Thus, targeting the specific molecular markers in synaptosomes may be critical for the development of mechanism-directed therapies against VaD.
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Affiliation(s)
- Cuicui Yang
- Department of Clinical Trial Center, Beijing Tiantan Hospital, Capital Medical University, No.119 South Fourth Ring West Road, Beijing, 100070, China.
- Department of Pharmacy, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China.
| | - Cengceng Zheng
- Department of Pharmacy, Xuanwu Hospital of Capital Medical University, Beijing, 100053, China
| | - Yuming Zhuang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing, 100069, China
| | - Shuhong Xu
- Department of Clinical Trial Center, Beijing Tiantan Hospital, Capital Medical University, No.119 South Fourth Ring West Road, Beijing, 100070, China
| | - Jian Li
- Department of Clinical Trial Center, Beijing Tiantan Hospital, Capital Medical University, No.119 South Fourth Ring West Road, Beijing, 100070, China
| | - Chaoying Hu
- Phase I Clinical Trial Unit, Beijing Ditan Hospital of Capital Medical University, No. 8 East Jingshun Road, Beijing, 100015, China.
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2
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Wang HY, Cecon E, Dam J, Pei Z, Jockers R, Burns LH. Simufilam Reverses Aberrant Receptor Interactions of Filamin A in Alzheimer's Disease. Int J Mol Sci 2023; 24:13927. [PMID: 37762230 PMCID: PMC10531384 DOI: 10.3390/ijms241813927] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/29/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Simufilam is a novel oral drug candidate in Phase 3 clinical trials for Alzheimer's disease (AD) dementia. This small molecule binds an altered form of filamin A (FLNA) that occurs in AD. This drug action disrupts FLNA's aberrant linkage to the α7 nicotinic acetylcholine receptor (α7nAChR), thereby blocking soluble amyloid beta1-42 (Aβ42)'s signaling via α7nAChR that hyperphosphorylates tau. Here, we aimed to clarify simufilam's mechanism. We now show that simufilam reduced Aβ42 binding to α7nAChR with a 10-picomolar IC50 using time-resolved fluorescence resonance energy transfer (TR-FRET), a robust technology to detect highly sensitive molecular interactions. We also show that FLNA links to multiple inflammatory receptors in addition to Toll-like receptor 4 (TLR4) in postmortem human AD brains and in AD transgenic mice: TLR2, C-X-C chemokine receptor type 4 (CXCR4), C-C chemokine receptor type 5 (CCR5), and T-cell co-receptor cluster of differentiation 4 (CD4). These aberrant FLNA linkages, which can be induced in a healthy control brain by Aβ42 incubation, were disrupted by simufilam. Simufilam reduced inflammatory cytokine release from Aβ42-stimulated human astrocytes. In the AD transgenic mice, CCR5-G protein coupling was elevated, indicating persistent activation. Oral simufilam reduced both the FLNA-CCR5 linkage and the CCR5-G protein coupling in these mice, while restoring CCR5's responsivity to C-C chemokine ligand 3 (CCL3). By disrupting aberrant FLNA-receptor interactions critical to AD pathogenic pathways, simufilam may promote brain health.
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Affiliation(s)
- Hoau-Yan Wang
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, New York, NY 10031, USA; (H.-Y.W.); (Z.P.)
- Department of Biology and Neuroscience, Graduate School, City University of New York, New York, NY 10016, USA
| | - Erika Cecon
- Institut Cochin, INSERM, CNRS, Université Paris Cité, 75014 Paris, France; (E.C.); (J.D.); (R.J.)
| | - Julie Dam
- Institut Cochin, INSERM, CNRS, Université Paris Cité, 75014 Paris, France; (E.C.); (J.D.); (R.J.)
| | - Zhe Pei
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, New York, NY 10031, USA; (H.-Y.W.); (Z.P.)
| | - Ralf Jockers
- Institut Cochin, INSERM, CNRS, Université Paris Cité, 75014 Paris, France; (E.C.); (J.D.); (R.J.)
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3
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Berson E, Gajera CR, Phongpreecha T, Perna A, Bukhari SA, Becker M, Chang AL, De Francesco D, Espinosa C, Ravindra NG, Postupna N, Latimer CS, Shively CA, Register TC, Craft S, Montine KS, Fox EJ, Keene CD, Bendall SC, Aghaeepour N, Montine TJ. Cross-species comparative analysis of single presynapses. Sci Rep 2023; 13:13849. [PMID: 37620363 PMCID: PMC10449792 DOI: 10.1038/s41598-023-40683-8] [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] [Received: 03/13/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023] Open
Abstract
Comparing brain structure across species and regions enables key functional insights. Leveraging publicly available data from a novel mass cytometry-based method, synaptometry by time of flight (SynTOF), we applied an unsupervised machine learning approach to conduct a comparative study of presynapse molecular abundance across three species and three brain regions. We used neural networks and their attractive properties to model complex relationships among high dimensional data to develop a unified, unsupervised framework for comparing the profile of more than 4.5 million single presynapses among normal human, macaque, and mouse samples. An extensive validation showed the feasibility of performing cross-species comparison using SynTOF profiling. Integrative analysis of the abundance of 20 presynaptic proteins revealed near-complete separation between primates and mice involving synaptic pruning, cellular energy, lipid metabolism, and neurotransmission. In addition, our analysis revealed a strong overlap between the presynaptic composition of human and macaque in the cerebral cortex and neostriatum. Our unique approach illuminates species- and region-specific variation in presynapse molecular composition.
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Affiliation(s)
- Eloïse Berson
- Department of Pathology, Stanford University, 300 Pasteur Dr., Stanford, CA, 94304, USA
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
| | - Chandresh R Gajera
- Department of Pathology, Stanford University, 300 Pasteur Dr., Stanford, CA, 94304, USA
| | - Thanaphong Phongpreecha
- Department of Pathology, Stanford University, 300 Pasteur Dr., Stanford, CA, 94304, USA
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
| | - Amalia Perna
- Department of Pathology, Stanford University, 300 Pasteur Dr., Stanford, CA, 94304, USA
| | - Syed A Bukhari
- Department of Pathology, Stanford University, 300 Pasteur Dr., Stanford, CA, 94304, USA
| | - Martin Becker
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
| | - Alan L Chang
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
| | - Davide De Francesco
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
| | - Camilo Espinosa
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
| | - Neal G Ravindra
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
| | - Nadia Postupna
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA, USA
| | - Caitlin S Latimer
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA, USA
| | - Carol A Shively
- Department of Pathology/Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Thomas C Register
- Department of Pathology/Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Suzanne Craft
- Department of Internal Medicine-Geriatrics, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Kathleen S Montine
- Department of Pathology, Stanford University, 300 Pasteur Dr., Stanford, CA, 94304, USA
| | - Edward J Fox
- Department of Pathology, Stanford University, 300 Pasteur Dr., Stanford, CA, 94304, USA
| | - C Dirk Keene
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA, USA
| | - Sean C Bendall
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
| | - Nima Aghaeepour
- Department of Anesthesiology, Perioperative, and Pain Medicine, Stanford University, Stanford, CA, USA
- Department of Pediatrics, Stanford University, Stanford, CA, USA
- Department of Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Thomas J Montine
- Department of Pathology, Stanford University, 300 Pasteur Dr., Stanford, CA, 94304, USA.
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Wang S, Li B, Solomon V, Fonteh A, Rapoport SI, Bennett DA, Arvanitakis Z, Chui HC, Sullivan PM, Yassine HN. Calcium-dependent cytosolic phospholipase A 2 activation is implicated in neuroinflammation and oxidative stress associated with ApoE4. Mol Neurodegener 2022; 17:42. [PMID: 35705959 PMCID: PMC9202185 DOI: 10.1186/s13024-022-00549-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 06/03/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Apolipoprotein E4 (APOE4) is associated with a greater response to neuroinflammation and the risk of developing late-onset Alzheimer's disease (AD), but the mechanisms for this association are not clear. The activation of calcium-dependent cytosolic phospholipase A2 (cPLA2) is involved in inflammatory signaling and is elevated within the plaques of AD brains. The relation between APOE4 genotype and cPLA2 activity is not known. METHODS Mouse primary astrocytes, mouse and human brain samples differing by APOE genotypes were collected for measuring cPLA2 expression, phosphorylation, and activity in relation to measures of inflammation and oxidative stress. RESULTS Greater cPLA2 phosphorylation, cPLA2 activity and leukotriene B4 (LTB4) levels were identified in ApoE4 compared to ApoE3 in primary astrocytes, brains of ApoE-targeted replacement (ApoE-TR) mice, and in human brain homogenates from the inferior frontal cortex of persons with AD dementia carrying APOE3/4 compared to APOE3/3. Higher phosphorylated p38 MAPK but not ERK1/2 was found in ApoE4 primary astrocytes and mouse brains than that in ApoE3. Greater cPLA2 translocation to cytosol was observed in human postmortem frontal cortical synaptosomes with recombinant ApoE4 than ApoE3 ex vivo. In ApoE4 astrocytes, the greater levels of LTB4, reactive oxygen species (ROS), and inducible nitric oxide synthase (iNOS) were reduced after cPLA2 inhibition. CONCLUSIONS Our findings implicate greater activation of cPLA2 signaling system with APOE4, which could represent a potential drug target for mitigating the increased neuroinflammation with APOE4 and AD.
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Affiliation(s)
- Shaowei Wang
- Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Boyang Li
- Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Victoria Solomon
- Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Alfred Fonteh
- Huntington Medical Research Institutes, Pasadena, CA USA
| | | | - David A. Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL USA
| | - Zoe Arvanitakis
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL USA
| | - Helena C. Chui
- Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Patrick M. Sullivan
- Department of Medicine, Duke University Medical Center, Durham Veterans Health Administration Medical Center’s Geriatric Research, Education and Clinical Center, Durham, NC USA
| | - Hussein N. Yassine
- Keck School of Medicine, University of Southern California, Los Angeles, CA USA
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5
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Gajera CR, Fernandez R, Postupna N, Montine KS, Keene CD, Bendall SC, Montine TJ. Mass Synaptometry: Applying Mass Cytometry to Single Synapse Analysis. Methods Mol Biol 2022; 2417:69-88. [PMID: 35099792 PMCID: PMC8820390 DOI: 10.1007/978-1-0716-1916-2_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Synaptic degeneration is one of the earliest and phenotypically most significant features associated with numerous neurodegenerative conditions, including Alzheimer's and Parkinson's diseases. Synaptic changes are also known to be important in neurocognitive disorders such as schizophrenia and autism spectrum disorders. Several labs, including ours, have demonstrated that conventional (fluorescence-based) flow cytometry of individual synaptosomes is a robust and reproducible method. However, the repertoire of probes needed to assess comprehensively the type of synapse, pathologic proteins (including protein products of risk genes discovered in GWAS), and markers of stress and injury far exceeds what is achievable with conventional flow cytometry. We recently developed a method that applies CyTOF (Cytometry by Time-Of-Flight mass spectrometry) to high-dimensional analysis of individual human synaptosomes, overcoming many of the multiplexing limitations of conventional flow cytometry. We call this new method Mass Synaptometry. Here we describe the preparation of synaptosomes from human and mouse brain, the generation and quality control of the "SynTOF" (Synapse by Time-Of-Flight mass spectrometry) antibody panel, the staining protocol, and CyTOF parameter setup for acquisition, post-acquisition processing, and analysis.
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Affiliation(s)
- Chandresh R. Gajera
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Rosemary Fernandez
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Nadia Postupna
- Department of Pathology, University of Washington, Seattle, WA, United States
| | - Kathleen S. Montine
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - C. Dirk Keene
- Department of Pathology, University of Washington, Seattle, WA, United States
| | - Sean C. Bendall
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Thomas J. Montine
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
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6
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Gajera CR, Fernandez R, Montine KS, Fox EJ, Mrdjen D, Postupna NO, Keene CD, Bendall SC, Montine TJ. Mass-tag barcoding for multiplexed analysis of human synaptosomes and other anuclear events. Cytometry A 2021; 99:939-945. [PMID: 33818911 PMCID: PMC8590852 DOI: 10.1002/cyto.a.24340] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/27/2021] [Accepted: 03/17/2021] [Indexed: 12/17/2022]
Abstract
Mass-tag cell barcoding has increased the throughput, multiplexing, and robustness of multiple cytometry approaches. Previously, we adapted mass cytometry for cells to analyze synaptosome preparations (mass synaptometry or SynTOF), extending mass cytometry to these smaller, anuclear particles. To improve throughput and individual event resolution, we report here the application of palladium-based barcoding in human synaptosomes. Up to 20 individual samples, each with a unique combinatorial barcode, were pooled for labeling with an antibody cocktail. Our synaptosome protocol used six palladium-based barcoding reagents, and in combination with sequential gating increased the identification of presynaptic events approximately fourfold. These same parameters also efficiently resolved two other anuclear particles: human red blood cells and platelets. The addition of palladium-based mass-tag barcoding to our approach improves mass cytometry of synaptic particles.
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Affiliation(s)
| | - Rosemary Fernandez
- Department of Pathology, Stanford University, Stanford, CA, United States
| | | | - Edward J. Fox
- Department of Pathology, Stanford University, Stanford, CA, United States
| | - Dunja Mrdjen
- Department of Pathology, Stanford University, Stanford, CA, United States
| | - Nadia O. Postupna
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States
| | - C. Dirk Keene
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, United States
| | - Sean C. Bendall
- Department of Pathology, Stanford University, Stanford, CA, United States
| | - Thomas J. Montine
- Department of Pathology, Stanford University, Stanford, CA, United States
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7
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Miller KD, Matullo C, Williams R, Jones CB, Rall GF. Murine BST2/tetherin promotes measles virus infection of neurons. Virology 2021; 563:38-43. [PMID: 34416448 DOI: 10.1016/j.virol.2021.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/06/2021] [Accepted: 08/11/2021] [Indexed: 11/15/2022]
Abstract
BST2/tetherin is a transmembrane protein with antiviral activity; it is synthesized following exposure to interferons, and restricts the release of budding virus particles by tethering them to the host cell membrane. We previously showed that BST2 is induced in primary neurons following measles virus (MV) infection or type I interferon; however, BST2 was dispensable for protection against challenge with neuron-restricted MV. Here, we define the contribution of BST-2 in neuronal MV infection. Surprisingly, and in contrast to its antiviral role in non-neuronal cells, murine BST2 promotes MV infection in brains of permissive mice and in primary neuron cultures. Moreover, BST2 expression was predominantly observed in the non-synaptic fraction of purified neurons. These studies highlight a cell-type dependent role of a well-characterized antiviral protein in enhancing neuronal infection.
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Affiliation(s)
- Katelyn D Miller
- Program in Cell and Molecular Biology, University of Pennsylvania, Philadelphia, PA, USA; Program in Blood Cell Development and Function, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Christine Matullo
- Program in Blood Cell Development and Function, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Riley Williams
- Program in Blood Cell Development and Function, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Carli B Jones
- Program in Blood Cell Development and Function, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Glenn F Rall
- Program in Cell and Molecular Biology, University of Pennsylvania, Philadelphia, PA, USA; Program in Blood Cell Development and Function, Fox Chase Cancer Center, Philadelphia, PA, USA.
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8
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Grubisha MJ, Sweet RA, MacDonald ML. Investigating Post-translational Modifications in Neuropsychiatric Disease: The Next Frontier in Human Post-mortem Brain Research. Front Mol Neurosci 2021; 14:689495. [PMID: 34335181 PMCID: PMC8322442 DOI: 10.3389/fnmol.2021.689495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/18/2021] [Indexed: 12/27/2022] Open
Abstract
Gene expression and translation have been extensively studied in human post-mortem brain tissue from subjects with psychiatric disease. Post-translational modifications (PTMs) have received less attention despite their implication by unbiased genetic studies and importance in regulating neuronal and circuit function. Here we review the rationale for studying PTMs in psychiatric disease, recent findings in human post-mortem tissue, the required controls for these types of studies, and highlight the emerging mass spectrometry approaches transforming this research direction.
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Affiliation(s)
- Melanie J. Grubisha
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Robert A. Sweet
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Matthew L. MacDonald
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
- Biomedical Mass Spectrometry Center, University of Pittsburgh, Pittsburgh, PA, United States
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9
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Hacioglu C, Kar F, Kanbak G. Ex Vivo Investigation of Bexarotene and Nicotinamide Function as a Protectıve Agent on Rat Synaptosomes Treated with Aβ(1-42). Neurochem Res 2021; 46:804-818. [PMID: 33428094 DOI: 10.1007/s11064-020-03216-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/19/2020] [Accepted: 12/23/2020] [Indexed: 01/09/2023]
Abstract
In this study, we were aimed to investigate the neuroprotective effects of bexarotene and nicotinamide in synaptosomes incubated with amyloid-beta (Aβ). Our study consists of 2 parts, in vivo and in vitro. In the in vivo section, twenty-four Wistar albino male rats were divided into 4 groups (control, dimethyl sulfoxide (DMSO), nicotinamide and bexarotene) with six animals in each group. DMSO(1%), nicotinamide(100 mg/kg) and bexarotene(0.1 mg/kg) were administered intraperitoneally to animals in the experimental groups for seven days. In the in vitro part of our study, three different isolation methods were used to obtain the synaptosomes from the brain tissue. Total antioxidant capacity(TAS), total oxidant capacity(TOS), cleaved caspase 3(CASP3), cytochrome c(Cyt c), sirtuin 1(SIRT1), peroxisome proliferator-activated receptor gamma(PPARγ) and poly(ADP-ribose) polymerase-1(PARP-1) levels in the synaptosomes incubated with a concentration of 10 µM Aβ(1-42) were measured by enzyme-linked immunosorbent assay method. Biochemical analysis and histopathological examinations in serum and brain samples showed that DMSO, nicotinamide and bexarotene treatments did not cause any damage to the rat brain tissue. We found that in vitro Aβ(1-42) administration decreased TAS, SIRT1 and PPARγ levels in synaptosomes while increasing TOS, CASP3, Cyt c, and PARP1 levels. Nicotinamide treatment suppressed oxidative stress and apoptosis by supporting antioxidant capacity and increased PPARγ through SIRT1 activation, causing PARP1 to decrease. On the other hand, bexarotene caused a moderate increase in SIRT1 levels with PPARγ activation. Consequently, we found that nicotinamide can be more effective than bexarotene in AD pathogenesis by regulating mitochondrial functions in synaptosomes.
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Affiliation(s)
- Ceyhan Hacioglu
- Department of Medical Biochemistry, Faculty of Medicine, Duzce University, Duzce, Turkey.
| | - Fatih Kar
- Department of Medical Biochemistry, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey
| | - Gungor Kanbak
- Department of Medical Biochemistry, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey
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10
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Exosomal tau with seeding activity is released from Alzheimer's disease synapses, and seeding potential is associated with amyloid beta. J Transl Med 2021; 101:1605-1617. [PMID: 34462532 PMCID: PMC8590975 DOI: 10.1038/s41374-021-00644-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 01/23/2023] Open
Abstract
Synaptic transfer of tau has long been hypothesized from the human pathology pattern and has been demonstrated in vitro and in vivo, but the precise mechanisms remain unclear. Extracellular vesicles such as exosomes have been suggested as a mechanism, but not all tau is exosomal. The present experiments use a novel flow cytometry assay to quantify depolarization of synaptosomes by KCl after loading with FM2-10, which induces a fluorescence reduction associated with synaptic vesicle release; the degree of reduction in cryopreserved human samples equaled that seen in fresh mouse synaptosomes. Depolarization induced the release of vesicles in the size range of exosomes, along with tetraspanin markers of extracellular vesicles. A number of tau peptides were released, including tau oligomers; released tau was primarily unphosphorylated and C-terminal truncated, with Aβ release just above background. When exosomes were immunopurified from release supernatants, a prominent tau band showed a dark smeared appearance of SDS-stable oligomers along with the exosomal marker syntenin-1, and these exosomes induced aggregation in the HEK tau biosensor assay. However, the flow-through did not seed aggregation. Size exclusion chromatography of purified released exosomes shows faint signals from tau in the same fractions that show a CD63 band, an exosomal size signal, and seeding activity. Crude synaptosomes from control, tauopathy, and AD cases demonstrated lower seeding in tauopathy compared to AD that is correlated with the measured Aβ42 level. These results show that AD synapses release exosomal tau that is C-terminal-truncated, oligomeric, and with seeding activity that is enhanced by Aβ. Taken together with previous findings, these results are consistent with a direct prion-like heterotypic seeding of tau by Aβ within synaptic terminals, with subsequent loading of aggregated tau onto exosomes that are released and competent for tau seeding activity.
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11
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Kumar S, Reddy PH. The role of synaptic microRNAs in Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165937. [PMID: 32827646 PMCID: PMC7680400 DOI: 10.1016/j.bbadis.2020.165937] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/04/2020] [Accepted: 08/17/2020] [Indexed: 12/11/2022]
Abstract
Structurally and functionally active synapses are essential for neurotransmission and for maintaining normal synaptic and cognitive functions. Researchers have found that synaptic dysfunction is associated with the onset and progression of neurodegenerative diseases, such as Alzheimer's disease (AD), and synaptic dysfunction is even one of the main physiological hallmarks of AD. MiRNAs are present in small, subcellular compartments of the neuron such as neural dendrites, synaptic vesicles, and synaptosomes are known as synaptic miRNAs. Synaptic miRNAs involved in governing multiple synaptic functions that lead to healthy brain functioning and synaptic activity. However, the precise role of synaptic miRNAs has not been determined in AD progression. This review emphasizes the presence of miRNAs at the synapse, synaptic compartments and roles of miRNAs in multiple synaptic functions. We focused on synaptic miRNAs alteration in AD, and how the modulation of miRNAs effect the synaptic functions in AD. We also discussed the impact of synaptic miRNAs in AD progression concerning the synaptic ATP production, mitochondrial function, and synaptic activity.
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Affiliation(s)
- Subodh Kumar
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
| | - P Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department Public Health, Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Speech, Language and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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Ahmad F, Liu P. Synaptosome as a tool in Alzheimer's disease research. Brain Res 2020; 1746:147009. [PMID: 32659233 DOI: 10.1016/j.brainres.2020.147009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/21/2020] [Accepted: 07/04/2020] [Indexed: 12/29/2022]
Abstract
Synapse dysfunction is an integral feature of Alzheimer's disease (AD) pathophysiology. In fact, prodromal manifestation of structural and functional deficits in synapses much prior to appearance of overt pathological hallmarks of the disease indicates that AD might be considered as a degenerative disorder of the synapses. Several research instruments and techniques have allowed us to study synaptic function and plasticity and their alterations in pathological conditions, such as AD. One such tool is the biochemically isolated preparations of detached and resealed synaptic terminals, the "synaptosomes". Because of the preservation of many of the physiological processes such as metabolic and enzymatic activities, synaptosomes have proved to be an indispensable ex vivo model system to study synapse physiology both when isolated from fresh or cryopreserved tissues, and from animal or human post-mortem tissues. This model system has been tremendously successful in the case of post-mortem tissues because of their accessibility relative to acute brain slices or cultures. The current review details the use of synaptosomes in AD research and its potential as a valuable tool in furthering our understanding of the pathogenesis and in devising and testing of therapeutic strategies for the disease.
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Affiliation(s)
- Faraz Ahmad
- Department of Anatomy, School of Biomedical Sciences, Brain Research New Zealand, University of Otago, Dunedin, New Zealand.
| | - Ping Liu
- Department of Anatomy, School of Biomedical Sciences, Brain Research New Zealand, University of Otago, Dunedin, New Zealand
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Apolipoprotein E/Amyloid-β Complex Accumulates in Alzheimer Disease Cortical Synapses via Apolipoprotein E Receptors and Is Enhanced by APOE4. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:1621-1636. [PMID: 31108099 DOI: 10.1016/j.ajpath.2019.04.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 04/08/2019] [Accepted: 04/11/2019] [Indexed: 01/08/2023]
Abstract
Apolipoprotein E (apoE) colocalizes with amyloid-β (Aβ) in Alzheimer disease (AD) plaques and in synapses, and evidence suggests that direct interactions between apoE and Aβ are important for apoE's effects in AD. The present work examines the hypothesis that apoE receptors mediate uptake of apoE/Aβ complex into synaptic terminals. Western blot analysis shows multiple SDS-stable assemblies in synaptosomes from human AD cortex; apoE/Aβ complex was markedly increased in AD compared with aged control samples. Complex formation between apoE and Aβ was confirmed by coimmunoprecipitation experiments. The apoE receptors low-density lipoprotein receptor (LDLR) and LDLR-related protein 1 (LRP1) were quantified in synaptosomes using flow cytometry, revealing up-regulation of LRP1 in early- and late-stage AD. Dual-labeling flow cytometry analysis of LRP1- and LDLR positives indicate most (approximately 65%) of LDLR and LRP1 is associated with postsynaptic density-95 (PSD-95)-positive synaptosomes, indicating that remaining LRP1 and LDLR receptors are exclusively presynaptic. Flow cytometry analysis of Nile red labeling revealed a reduction in cholesterol esters in AD synaptosomes. Dual-labeling experiments showed apoE and Aβ concentration into LDLR and LRP1-positive synaptosomes, along with free and esterified cholesterol. Synaptic Aβ was increased by apoE4 in control and AD samples. These results are consistent with uptake of apoE/Aβ complex and associated lipids into synaptic terminals, with subsequent Aβ clearance in control synapses and accumulation in AD synapses.
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Gajera CR, Fernandez R, Postupna N, Montine KS, Fox EJ, Tebaykin D, Angelo M, Bendall SC, Keene CD, Montine TJ. Mass synaptometry: High-dimensional multi parametric assay for single synapses. J Neurosci Methods 2018; 312:73-83. [PMID: 30465796 DOI: 10.1016/j.jneumeth.2018.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/09/2018] [Accepted: 11/10/2018] [Indexed: 01/19/2023]
Abstract
BACKGROUND Synaptic alterations, especially presynaptic changes, are cardinal features of neurodegenerative diseases and strongly correlate with cognitive decline. NEW METHOD We report "Mass Synaptometry" for the high-dimensional analysis of individual human synaptosomes, enriched nerve terminals from brain. This method was adapted from cytometry by time-of-flight mass spectrometry (CyTOF), which is commonly used for single-cell analysis of immune and blood cells. RESULT Here we overcome challenges for single synapse analysis by optimizing synaptosome preparations, generating a 'SynTOF panel,' recalibrating acquisition settings, and applying computational analyses. Through the analysis of 390,000 individual synaptosomes, we also provide proof-of principle validation by characterizing changes in synaptic diversity in Lewy Body Disease (LBD), Alzheimer's disease and normal brain. COMPARISON WITH EXISTING METHOD(S) Current imaging methods to study synapses in humans are capable of analyzing a limited number of synapses, and conventional flow cytometric techniques are typically restricted to fewer than 6 parameters. Our method allows for the simultaneous detection of 34 parameters from tens of thousands of individual synapses. CONCLUSION We applied Mass Synaptometry to analyze 34 parameters simultaneously on more than 390,000 synaptosomes from 13 human brain samples. This new approach revealed regional and disease-specific changes in synaptic phenotypes, including validation of this method with the expected changes in the molecular composition of striatal dopaminergic synapses in Lewy body disease and Alzheimer's disease. Mass synaptometry enables highly parallel molecular profiling of individual synaptic terminals.
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Affiliation(s)
- Chandresh R Gajera
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Rosemary Fernandez
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Nadia Postupna
- Department of Pathology, University of Washington, Seattle, WA, United States
| | - Kathleen S Montine
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Edward J Fox
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Dmitry Tebaykin
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Michael Angelo
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - Sean C Bendall
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States
| | - C Dirk Keene
- Department of Pathology, University of Washington, Seattle, WA, United States
| | - Thomas J Montine
- Department of Pathology, Stanford University Medical Center, Stanford, CA, United States.
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SMPL Synaptic Membranes: Nanodisc-Mediated Synaptic Membrane Mimetics Expand the Toolkit for Drug Discovery and the Molecular Cell Biology of Synapses. NEUROMETHODS 2018. [DOI: 10.1007/978-1-4939-8739-9_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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The Study of Postmortem Human Synaptosomes for Understanding Alzheimer's Disease and Other Neurological Disorders: A Review. Neurol Ther 2017; 6:57-68. [PMID: 28733958 PMCID: PMC5520816 DOI: 10.1007/s40120-017-0070-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Indexed: 12/12/2022] Open
Abstract
Synaptic dysfunction is thought to play important roles in the pathophysiology of many neurological diseases, including Alzheimer’s disease, Parkinson’s disease, and schizophrenia. Over the past few decades, there have been systematic efforts to collect postmortem brain tissues via autopsies, leading to the establishment of dozens of human brain banks around the world. From cryopreserved human brain tissues, it is possible to isolate detached-and-resealed synaptic terminals termed synaptosomes, which remain metabolically and enzymatically active. Synaptosomes have become important model systems for studying human synaptic functions, being much more accessible than ex vivo brain slices or primary neuronal cultures. Here we review recent advances in the establishment of human brain banks, the isolation of synaptosomes, their biological activities, and various analytical techniques for investigating their biochemical and ultrastructural properties. There are unique insights to be gained by directly examining human synaptosomes, which cannot be substituted by animal models. We will also discuss how human synaptosome research has contributed to better understanding of neurological disorders, especially Alzheimer’s disease.
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Postupna N, Latimer CS, Larson EB, Sherfield E, Paladin J, Shively CA, Jorgensen MJ, Andrews RN, Kaplan JR, Crane PK, Montine KS, Craft S, Keene CD, Montine TJ. Human Striatal Dopaminergic and Regional Serotonergic Synaptic Degeneration with Lewy Body Disease and Inheritance of APOE ε4. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:884-895. [PMID: 28212814 DOI: 10.1016/j.ajpath.2016.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 12/10/2016] [Accepted: 12/20/2016] [Indexed: 01/22/2023]
Abstract
Cognitive impairment in older individuals is a complex trait that in population-based studies most commonly derives from an individually varying mixture of Alzheimer disease, Lewy body disease, and vascular brain injury. We investigated the molecular composition of synaptic particles from three sources: consecutive rapid autopsy brains from the Adult Changes in Thought Study, a population-based cohort; four aged nonhuman primate brains optimally processed for molecular investigation; and targeted replacement transgenic mice homozygous for APOE ε4. Our major goal was to characterize the molecular composition of human synaptic particles in regions of striatum and prefrontal cortex. We performed flow cytometry to measure six markers of synaptic subtypes, as well as amyloid β 42 and paired helical filament tau. Our results showed selective degeneration of dopaminergic terminals throughout the striatum in individuals with Lewy body disease, and serotonergic degeneration in human ventromedial caudate nucleus from individuals with an APOE ε4 allele. Similar results were seen in mouse caudate nucleus homozygous for APOE ε4 via targeted replacement. Together, extension of these clinical, pathologic, and genetic associations from tissue to the synaptic compartment of cerebral cortex and striatum strongly supports our approach for accurately observing the molecular composition of human synapses by flow cytometry.
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Affiliation(s)
- Nadia Postupna
- Department of Pathology, University of Washington, Seattle, Washington
| | - Caitlin S Latimer
- Department of Pathology, University of Washington, Seattle, Washington
| | - Eric B Larson
- Group Health Research Institute, Seattle, Washington
| | - Emily Sherfield
- Department of Pathology, University of Washington, Seattle, Washington
| | - Julie Paladin
- Department of Pathology, University of Washington, Seattle, Washington
| | - Carol A Shively
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Matthew J Jorgensen
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Rachel N Andrews
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jay R Kaplan
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Paul K Crane
- Department of Medicine, University of Washington, Seattle, Washington
| | | | - Suzanne Craft
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - C Dirk Keene
- Department of Pathology, University of Washington, Seattle, Washington
| | - Thomas J Montine
- Department of Pathology, University of Washington, Seattle, Washington.
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Tenreiro P, Rebelo S, Martins F, Santos M, Coelho ED, Almeida M, Alves de Matos AP, da Cruz E Silva OAB. Comparison of simple sucrose and percoll based methodologies for synaptosome enrichment. Anal Biochem 2016; 517:1-8. [PMID: 27771393 DOI: 10.1016/j.ab.2016.10.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/16/2016] [Accepted: 10/18/2016] [Indexed: 01/20/2023]
Abstract
Synaptosomes are isolated nerve terminals. They represent an extremely attractive in vitro model system to study synaptic physiology since they preserve morphological and functional characteristics of the synapse. As such they have been used to investigate synaptic dysfunctions associated with neuropathologies like Alzheimer's disease. In the present work two simple methodologies for isolating synaptosomal-enriched fractions were compared for the first time. The starting points of both protocols were rat cortical or hippocampal homogenized tissues that underwent several differential centrifugation steps followed by a final purification of synaptosomal-enriched fractions using either a Percoll gradient or a Sucrose gradient. Comparison of the fractions obtained was carried out, using both biochemical and electron microscopy approaches. In the biochemical analysis the protein levels of pre-synaptic, post-synaptic, nuclear and mitochondrial markers were evaluated. Additional characterization of the synaptosomal-enriched fractions was performed using transmission electron microscopy. In summary, the results indicate that under the conditions tested the Sucrose based protocol is more efficient for the isolation of synaptosomal-enriched fractions from both neuronal tissues, being particularly efficient for hippocampus that is a less abundant brain tissue. Further, the sucrose protocol apparently results in a higher yield of viable synaptosomes suitable for further assays, including structural and functional studies of synapses; making this an attractive procedure to study processes associated with neuropathologies.
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Affiliation(s)
- P Tenreiro
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
| | - S Rebelo
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal.
| | - F Martins
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
| | - M Santos
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
| | - E D Coelho
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
| | - M Almeida
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
| | - A P Alves de Matos
- Centro de Estudos do Ambiente e do Mar, Faculdade de Ciências da Universidade de Lisboa, Portugal; Centro de Investigação Interdisciplinar Egas Moniz, Monte de Caparica, Lisboa, Portugal
| | - O A B da Cruz E Silva
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
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Bilousova T, Miller CA, Poon WW, Vinters HV, Corrada M, Kawas C, Hayden EY, Teplow DB, Glabe C, Albay R, Cole GM, Teng E, Gylys KH. Synaptic Amyloid-β Oligomers Precede p-Tau and Differentiate High Pathology Control Cases. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:185-98. [PMID: 26718979 DOI: 10.1016/j.ajpath.2015.09.018] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 01/03/2023]
Abstract
Amyloid-β (Aβ) and hyperphosphorylated tau (p-tau) aggregates form the two discrete pathologies of Alzheimer disease (AD), and oligomeric assemblies of each protein are localized to synapses. To determine the sequence by which pathology appears in synapses, Aβ and p-tau were quantified across AD disease stages in parietal cortex. Nondemented cases with high levels of AD-related pathology were included to determine factors that confer protection from clinical symptoms. Flow cytometric analysis of synaptosome preparations was used to quantify Aβ and p-tau in large populations of individual synaptic terminals. Soluble Aβ oligomers were assayed by a single antibody sandwich enzyme-linked immunosorbent assay. Total in situ Aβ was elevated in patients with early- and late-stage AD dementia, but not in high pathology nondemented controls compared with age-matched normal controls. However, soluble Aβ oligomers were highest in early AD synapses, and this assay distinguished early AD cases from high pathology controls. Overall, synapse-associated p-tau did not increase until late-stage disease in human and transgenic rat cortex, and p-tau was elevated in individual Aβ-positive synaptosomes in early AD. These results suggest that soluble oligomers in surviving neocortical synaptic terminals are associated with dementia onset and suggest an amyloid cascade hypothesis in which oligomeric Aβ drives phosphorylated tau accumulation and synaptic spread. These results indicate that antiamyloid therapies will be less effective once p-tau pathology is developed.
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Affiliation(s)
- Tina Bilousova
- University of California Los Angeles School of Nursing, Los Angeles, California; Mary S. Easton Center for Alzheimer's Research at the University of California Los Angeles, Los Angeles, California
| | - Carol A Miller
- Departments of Pathology, Neurology, and the Program in Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, California
| | - Wayne W Poon
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California
| | - Harry V Vinters
- Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, California; Department of Pathology and Laboratory Medicine, University of California Los Angeles School of Medicine, Los Angeles, California
| | - Maria Corrada
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California; Department of Neurology, University of California Irvine, Irvine, California
| | - Claudia Kawas
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California; Department of Neurology, University of California Irvine, Irvine, California; Department of Neurobiology & Behavior, University of California Irvine, Irvine, California
| | - Eric Y Hayden
- Mary S. Easton Center for Alzheimer's Research at the University of California Los Angeles, Los Angeles, California; Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, California
| | - David B Teplow
- Mary S. Easton Center for Alzheimer's Research at the University of California Los Angeles, Los Angeles, California; Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, California
| | - Charles Glabe
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California
| | - Ricardo Albay
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California
| | - Gregory M Cole
- Mary S. Easton Center for Alzheimer's Research at the University of California Los Angeles, Los Angeles, California; Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, California; Department of Medicine, University of California Los Angeles School of Medicine, Los Angeles, California; Geriatric Research, Education and Clinical Center, VA Greater Los Angeles Healthcare System, Los Angeles, California
| | - Edmond Teng
- Mary S. Easton Center for Alzheimer's Research at the University of California Los Angeles, Los Angeles, California; Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, California; Geriatric Research, Education and Clinical Center, VA Greater Los Angeles Healthcare System, Los Angeles, California
| | - Karen H Gylys
- University of California Los Angeles School of Nursing, Los Angeles, California; Mary S. Easton Center for Alzheimer's Research at the University of California Los Angeles, Los Angeles, California.
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Wang S, Yu L, Yang H, Li C, Hui Z, Xu Y, Zhu X. Oridonin Attenuates Synaptic Loss and Cognitive Deficits in an Aβ1-42-Induced Mouse Model of Alzheimer's Disease. PLoS One 2016; 11:e0151397. [PMID: 26974541 PMCID: PMC4790895 DOI: 10.1371/journal.pone.0151397] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 02/26/2016] [Indexed: 12/31/2022] Open
Abstract
Synaptic loss induced by beta-amyloid (Aβ) plays a critical role in the pathophysiology of Alzheimer’s disease (AD), but the mechanisms underlying this process remain unknown. In this study, we found that oridonin (Ori) rescued synaptic loss induced by Aβ1–42in vivo and in vitro and attenuated the alterations in dendritic structure and spine density observed in the hippocampus of AD mice. In addition, Ori increased the expression of PSD-95 and synaptophysin and promoted mitochondrial activity in the synaptosomes of AD mice. Ori also activated the BDNF/TrkB/CREB signaling pathway in the hippocampus of AD mice. Furthermore, in the Morris water maze test, Ori reduced latency and searching distance and increased the number of platform crosses in AD mice. These data suggest that Ori might prevent synaptic loss and improve behavioral symptoms in Aβ1–42-induced AD mice.
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Affiliation(s)
- Sulei Wang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Linjie Yu
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
| | - Hui Yang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Chaosheng Li
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Zhen Hui
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
- Jiangsu Stroke Research Collaborative Group, Nanjing, PR China
- Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, PR China
- Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, PR China
- * E-mail: (YX); (XLZ)
| | - Xiaolei Zhu
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
- * E-mail: (YX); (XLZ)
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Sokolow S, Henkins KM, Bilousova T, Gonzalez B, Vinters HV, Miller CA, Cornwell L, Poon WW, Gylys KH. Pre-synaptic C-terminal truncated tau is released from cortical synapses in Alzheimer's disease. J Neurochem 2015; 133:368-79. [PMID: 25393609 DOI: 10.1111/jnc.12991] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/02/2014] [Accepted: 11/06/2014] [Indexed: 12/31/2022]
Abstract
The microtubule-associated protein tau has primarily been associated with axonal location and function; however, recent work shows tau release from neurons and suggests an important role for tau in synaptic plasticity. In our study, we measured synaptic levels of total tau using synaptosomes prepared from cryopreserved human postmortem Alzheimer's disease (AD) and control samples. Flow cytometry data show that a majority of synaptic terminals are highly immunolabeled with the total tau antibody (HT7) in both AD and control samples. Immunoblots of synaptosomal fractions reveal increases in a 20 kDa tau fragment and in tau dimers in AD synapses, and terminal-specific antibodies show that in many synaptosome samples tau lacks a C-terminus. Flow cytometry experiments to quantify the extent of C-terminal truncation reveal that only 15-25% of synaptosomes are positive for intact C-terminal tau. Potassium-induced depolarization demonstrates release of tau and tau fragments from pre-synaptic terminals, with increased release from AD compared to control samples. This study indicates that tau is normally highly localized to synaptic terminals in cortex where it is well-positioned to affect synaptic plasticity. Tau cleavage may facilitate tau aggregation as well as tau secretion and propagation of tau pathology from the pre-synaptic compartment in AD. Results demonstrate the abundance of tau, mainly C-terminal truncated tau, in synaptic terminals in aged control and in Alzheimer's disease (AD) samples. Tau fragments and dimers/oligomers are prominent in AD synapses. Following depolarization, tau release is potentiated in AD nerve terminals compared to aged controls. We hypothesize (i) endosomal release of the different tau peptides from AD synapses, and (ii) together with phosphorylation, fragmentation of synaptic tau exacerbates tau aggregation, synaptic dysfunction, and the spread of tau pathology in AD. Aβ = amyloid-beta.
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Affiliation(s)
- Sophie Sokolow
- UCLA School of Nursing, Los Angeles, California, USA; UCLA Brain Research Institute, Los Angeles, California, USA; UCLA Center for the Advancement of Gerontological Nursing Sciences, Los Angeles, California, USA; UCLA Clinical and Translational Science Institute, Los Angeles, California, USA
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Plum S, Steinbach S, Abel L, Marcus K, Helling S, May C. Proteomics in neurodegenerative diseases: Methods for obtaining a closer look at the neuronal proteome. Proteomics Clin Appl 2014; 9:848-71. [DOI: 10.1002/prca.201400030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 06/25/2014] [Accepted: 09/03/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Sarah Plum
- Medizinisches Proteom-Center; Funktionelle Proteomik; Ruhr-Universität Bochum; Bochum Germany
| | - Simone Steinbach
- Medizinisches Proteom-Center; Medical Proteomics/Bioanalytics; Ruhr-Universität Bochum; Bochum Germany
| | - Laura Abel
- Medizinisches Proteom-Center; Medical Proteomics/Bioanalytics; Ruhr-Universität Bochum; Bochum Germany
| | - Katrin Marcus
- Medizinisches Proteom-Center; Funktionelle Proteomik; Ruhr-Universität Bochum; Bochum Germany
| | - Stefan Helling
- Medizinisches Proteom-Center; Funktionelle Proteomik; Ruhr-Universität Bochum; Bochum Germany
| | - Caroline May
- Medizinisches Proteom-Center; Medical Proteomics/Bioanalytics; Ruhr-Universität Bochum; Bochum Germany
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Price KA, Varghese M, Sowa A, Yuk F, Brautigam H, Ehrlich ME, Dickstein DL. Altered synaptic structure in the hippocampus in a mouse model of Alzheimer's disease with soluble amyloid-β oligomers and no plaque pathology. Mol Neurodegener 2014; 9:41. [PMID: 25312309 PMCID: PMC4210526 DOI: 10.1186/1750-1326-9-41] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/27/2014] [Indexed: 11/16/2022] Open
Abstract
Background Mounting evidence suggests that soluble oligomers of amyloid-β (oAβ) represent the pertinent synaptotoxic form of Aβ in sporadic Alzheimer’s disease (AD); however, the mechanistic links between oAβ and synaptic degeneration remain elusive. Most in vivo experiments to date have been limited to examining the toxicity of oAβ in mouse models that also possess insoluble fibrillar Aβ (fAβ), and data generated from these models can lead to ambiguous interpretations. Our goal in the present study was to examine the effects of soluble oAβ on neuronal and synaptic structure in the amyloid precursor protein (APP) E693Q (“Dutch”) mouse model of AD, which develops intraneuronal accumulation of soluble oAβ with no detectable plaques in AD-relevant brain regions. We performed quantitative analyses of neuronal pathology, including dendrite morphology, spine density, and synapse ultrastructure in individual hippocampal CA1 neurons. Results When assessing neuronal morphology and complexity we observed significant alterations in apical but not in basal dendritic arbor length in Dutch mice compared to wild type. Moreover, Dutch mice exhibited a significant decrease in dendritic arborization with a decrease in dendritic length and number of intersections at 120 μm and 150 μm from the soma, respectively. We next examined synaptic parameters and found that while there were no differences in overall synaptic structure, Dutch mice displayed a significant reduction in the post-synaptic density (PSD) length of synapses on mushroom spines, in comparison to wild type littermates. Conclusion The structural alterations to individual neurons in Dutch mice along with the changes in larger dendritic spines support the Aβ oligomer hypothesis, which postulates that the early cognitive impairments that occur in AD are attributed to the accumulation of soluble oAβ first affecting at the synaptic level with subsequent structural disturbances and cellular degeneration. Electronic supplementary material The online version of this article (doi:10.1186/1750-1326-9-41) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | - Dara L Dickstein
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave L, Levy Place, Box 1639, New York, NY 10029, USA.
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cAMP-PKA phosphorylation of tau confers risk for degeneration in aging association cortex. Proc Natl Acad Sci U S A 2014; 111:5036-41. [PMID: 24707050 DOI: 10.1073/pnas.1322360111] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The pattern of neurodegeneration in Alzheimer's disease (AD) is very distinctive: neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau selectively affect pyramidal neurons of the aging association cortex that interconnect extensively through glutamate synapses on dendritic spines. In contrast, primary sensory cortices have few NFTs, even in late-stage disease. Understanding this selective vulnerability, and why advancing age is such a high risk factor for the degenerative process, may help to reveal disease etiology and provide targets for intervention. Our study has revealed age-related increase in cAMP-dependent protein kinase (PKA) phosphorylation of tau at serine 214 (pS214-tau) in monkey dorsolateral prefrontal association cortex (dlPFC), which specifically targets spine synapses and the Ca(2+)-storing spine apparatus. This increase is mirrored by loss of phosphodiesterase 4A from the spine apparatus, consistent with increase in cAMP-Ca(2+) signaling in aging spines. Phosphorylated tau was not detected in primary visual cortex, similar to the pattern observed in AD. We also report electron microscopic evidence of previously unidentified vesicular trafficking of phosphorylated tau in normal association cortex--in axons in young dlPFC vs. in spines in aged dlPFC--consistent with the transneuronal lesion spread reported in genetic rodent models. pS214-Tau was not observed in normal aged mice, suggesting that it arises with the evolutionary expansion of corticocortical connections in primates, crossing the threshold into NFTs and degeneration in humans. Thus, the cAMP-Ca(2+) signaling mechanisms, needed for flexibly modulating network strength in young association cortex, confer vulnerability to degeneration when dysregulated with advancing age.
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Ulrich H, Bocsi J, Glaser T, Tárnok A. Cytometry in the brain: studying differentiation to diagnostic applications in brain disease and regeneration therapy. Cell Prolif 2014; 47:12-9. [PMID: 24450810 DOI: 10.1111/cpr.12087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/02/2013] [Indexed: 12/30/2022] Open
Abstract
During brain development, a population of uniform embryonic cells migrates and differentiates into a large number of neural phenotypes - origin of the enormous complexity of the adult nervous system. Processes of cell proliferation, differentiation and programmed death of no longer required cells, do not occur only during embryogenesis, but are also maintained during adulthood and are affected in neurodegenerative and neuropsychiatric disease states. As neurogenesis is an endogenous response to brain injury, visible as proliferation (of to this moment silent stem or progenitor cells), its further stimulation can present a treatment strategy in addition to stem cell transfer for cell regeneration therapy. Concise techniques for studying such events in vitro and in vivo permit understanding of underlying mechanisms. Detection of subtle physiological alterations in brain cell proliferation and neurogenesis can be explored, that occur during environmental stimulation, exercise and ageing. Here, we have collected achievements in the field of basic research on applications of cytometry, including automated imaging for quantification of morphological or fluorescence-based parameters in cell cultures, towards imaging of three-dimensional brain architecture together with DNA content and proliferation data. Multi-parameter and more recently in vivo flow cytometry procedures, have been developed for quantification of phenotypic diversity and cell processes that occur during brain development as well as in adulthood, with importance for therapeutic approaches.
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Affiliation(s)
- H Ulrich
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, São Paulo, S.P 05508-900, Brazil
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Greve B, Sheikh-Mounessi F, Kemper B, Ernst I, Götte M, Eich HT. Survivin, a target to modulate the radiosensitivity of Ewing's sarcoma. Strahlenther Onkol 2012; 188:1038-47. [PMID: 23053158 DOI: 10.1007/s00066-012-0223-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 08/06/2012] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND PURPOSE Radiotherapy constitutes an essential element in the multimodal therapy of Ewing's sarcoma. Compared to other sarcomas, Ewing tumors normally show a good response to radiotherapy. However, there are consistently tumors with a radioresistant phenotype, and the underlying mechanisms are not known in detail. Here we investigated the association between survivin protein expression and the radiosensitivity of Ewing's sarcoma in vitro. MATERIAL AND METHODS An siRNA-based knockdown approach was used to investigate the influence of survivin expression on cell proliferation, double-strand break (DSB) induction and repair, apoptosis and colony-forming ability in four Ewing's sarcoma cell lines with and without irradiation. RESULTS Survivin protein and mRNA were upregulated in all cell lines tested in a dose-dependent manner. As a result of survivin knockdown, STA-ET-1 cells showed reduced cell proliferation, an increased number of radiation-induced DSBs, and reduced repair. Apoptosis was increased by knockdown alone and increased further in combination with irradiation. Colony formation was significantly reduced by survivin knockdown in combination with irradiation. CONCLUSION Survivin is a radiation-inducible protein in Ewing's sarcoma and its down-regulation sensitizes cells toward irradiation. Survivin knockdown in combination with radiation inhibits cell proliferation, repair, and colony formation significantly and increases apoptosis more than each single treatment alone. This might open new perspectives in the radiation treatment of Ewing's sarcoma.
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Affiliation(s)
- B Greve
- Klinik und Poliklinik für Strahlentherapie -Radioonkologie, Universitätsklinikum Münster, Albert-Schweitzer Campus 1 Gebäude A1, 48149, Münster, Germany.
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