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Smukowski SN, Danyko C, Somberg J, Kaufman EJ, Course MM, Postupna N, Barker-Haliski M, Keene CD, Valdmanis PN. mRNA and circRNA mislocalization to synapses are key features of Alzheimer's disease. PLoS Genet 2024; 20:e1011359. [PMID: 39074152 DOI: 10.1371/journal.pgen.1011359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 07/02/2024] [Indexed: 07/31/2024] Open
Abstract
Proper transport of RNAs to synapses is essential for localized translation of proteins in response to synaptic signals and synaptic plasticity. Alzheimer's disease (AD) is a neurodegenerative disease characterized by accumulation of amyloid aggregates and hyperphosphorylated tau neurofibrillary tangles followed by widespread synapse loss. To understand whether RNA synaptic localization is impacted in AD, we performed RNA sequencing on synaptosomes and brain homogenates from AD patients and cognitively healthy controls. This resulted in the discovery of hundreds of mislocalized mRNAs in AD among frontal and temporal brain regions. Similar observations were found in an APPswe/PSEN1dE9 mouse model. Furthermore, major differences were observed among circular RNAs (circRNAs) localized to synapses in AD including two overlapping isoforms of circGSK3β, one upregulated, and one downregulated. Expression of these distinct isoforms affected tau phosphorylation in neuronal cells substantiating the importance of circRNAs in the brain and pointing to a new class of therapeutic targets.
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Affiliation(s)
- Samuel N Smukowski
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Cassidy Danyko
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, United States of America
- Fred Hutch Cancer Center, Basic Sciences Division, University of Washington, Seattle, Washington, United States of America
| | - Jenna Somberg
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, United States of America
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Eli J Kaufman
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, United States of America
| | - Meredith M Course
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, United States of America
- Department of Molecular Biology, Colorado College, Colorado Springs, Colorado, United States of America
| | - Nadia Postupna
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Melissa Barker-Haliski
- Department of Pharmacy, University of Washington School of Pharmacy, Seattle, Washington, United States of America
| | - C Dirk Keene
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Paul N Valdmanis
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
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Monaco M, Trebesova H, Grilli M. Muscarinic Receptors and Alzheimer's Disease: New Perspectives and Mechanisms. Curr Issues Mol Biol 2024; 46:6820-6835. [PMID: 39057049 PMCID: PMC11276210 DOI: 10.3390/cimb46070407] [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: 06/04/2024] [Revised: 06/28/2024] [Accepted: 06/29/2024] [Indexed: 07/28/2024] Open
Abstract
Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases on a global scale. Historically, this pathology has been linked to cholinergic transmission, and despite the scarcity of effective therapies, numerous alternative processes and targets have been proposed as potential avenues for comprehending this complex illness. Nevertheless, the fundamental pathophysiological mechanisms underpinning AD remain largely enigmatic, with a growing body of evidence advocating for the significance of muscarinic receptors in modulating the brain's capacity to adapt and generate new memories. This review summarizes the current state of the art in the field of muscarinic receptors' involvement in AD. A specific key factor was the relationship between comorbidity and the emergence of new mechanisms.
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Affiliation(s)
- Martina Monaco
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy; (M.M.); (H.T.)
| | - Hanna Trebesova
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy; (M.M.); (H.T.)
| | - Massimo Grilli
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, 16148 Genoa, Italy; (M.M.); (H.T.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 16148 Genoa, Italy
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Hacioglu C, Kar F, Sahin MC. Neurochemical Research of LOXBlock-1 and ZnSO 4 against Neurodegenerative Damage Induced by Amyloid Beta(1-42). Biol Trace Elem Res 2024; 202:3204-3214. [PMID: 37872362 DOI: 10.1007/s12011-023-03908-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/06/2023] [Indexed: 10/25/2023]
Abstract
Synaptosomes offer an intriguing ex vivo model system for investigating the molecular mechanisms of neurodegenerative processes. Lipoxygenases significantly affect the course of neurodegenerative diseases. Homeostasis of trace elements such as zinc is necessary for the continuity of brain functions. In this study, we purpose to determine whether LOXBlock-1, a 12/15 lipoxygenase inhibitor, and zinc sulfate (ZnSO4) provide any biochemical protection during neurodegenerative damage in synaptosomes induced by amyloid beta 1-42 (Aβ1-42). In this study, animals (30 Wistar Albino male rats 30) were divided into 5 groups (6 animals in each group): Control, 10µM Aβ1-42, 10µM Aβ1-42+25mM LOXBlock-1, 10µM Aβ1-42+10µM ZnSO4, and 10µM Aβ1-42+25mM LOXBlock-1+10µM ZnSO4. Synaptosomes were isolated from the rat cerebral cortex. Following, 8-hydroxy-2-deoxyguanosine (8-OHdG) levels, malondialdehyde (MDA) levels, adenosine deaminase (ADA) levels, reduced-glutathione (GSH) levels, neuronal nitric oxide synthase (nNOS) levels, acetylcholinesterase (AChE) activity, catalase (CAT) activity, and 8-OHdG levels in synaptosomes were detected according to the ELISA method. ADA and AChE expression and protein levels were analyzed. MDA, nNOS, AChE, and 8-OHdG levels in synaptosomes treated with Aβ1-42 resulted in an increase, while there was a decrease in ADA, GSH, and CAT levels (p<0.001 vs. control). Conversely, LOXBlock-1 and ZnSO4 treatments in synaptosomes treated with Aβ1-42 decreased MDA, nNOS, AChE, and 8-OHdG levels, while ADA, GSH, and CAT levels increased. Moreover, the most effective improvement was seen in the co-treatment group of LOXBlock-1 and ZnSO4. Our data showed that LOXBlock-1 and ZnSO4 co-treatment may protect against Aβ1-42 exposure in rat brain synaptosomes.
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Affiliation(s)
- Ceyhan Hacioglu
- Department of Biochemistry, Faculty of Pharmacy, Duzce University, Duzce, Turkey.
- Department of Medical Biochemistry, Faculty of Medicine, Duzce University, Duzce, Turkey.
| | - Fatih Kar
- Department of Medical Biochemistry, Faculty of Medicine, Kütahya Health Sciences University, Kütahya, Turkey
| | - Meryem Cansu Sahin
- Department of Medical Services and Techniques, Medical Imaging Techniques Program, Uşak University, Uşak, Turkey
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4
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Melnik M, Miyoshi E, Ma R, Corrada M, Kawas C, Bohannan R, Caraway C, Miller CA, Hinman JD, John V, Bilousova T, Gylys KH. Simultaneous isolation of intact brain cells and cell-specific extracellular vesicles from cryopreserved Alzheimer's disease cortex. J Neurosci Methods 2024; 406:110137. [PMID: 38626853 DOI: 10.1016/j.jneumeth.2024.110137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/25/2024] [Accepted: 04/12/2024] [Indexed: 04/21/2024]
Abstract
BACKGROUND The neuronal and gliaI populations within the brain are tightly interwoven, making isolation and study of large populations of a single cell type from brain tissue a major technical challenge. Concurrently, cell-type specific extracellular vesicles (EVs) hold enormous diagnostic and therapeutic potential in neurodegenerative disorders including Alzheimer's disease (AD). NEW METHOD Postmortem AD cortical samples were thawed and gently dissociated. Following filtration, myelin and red blood cell removal, cell pellets were immunolabeled with fluorescent antibodies and analyzed by flow cytometry. The cell pellet supernatant was applied to a triple sucrose cushion for brain EV isolation. RESULTS Neuronal, astrocyte and microglial cell populations were identified. Cell integrity was demonstrated using calcein AM, which is retained by cells with esterase activity and an intact membrane. For some experiments cell pellets were fixed, permeabilized, and immunolabeled for cell-specific markers. Characterization of brain small EV fractions showed the expected size, depletion of EV negative markers, and enrichment in positive and cell-type specific markers. COMPARISON WITH EXISTING METHODS AND CONCLUSIONS We optimized and integrated established protocols, aiming to maximize information obtained from each human autopsy brain sample. The uniqueness of our method lies in its capability to isolate cells and EVs from a single cryopreserved brain sample. Our results not only demonstrate the feasibility of isolating specific brain cell subpopulations for RNA-seq but also validate these subpopulations at the protein level. The accelerated study of EVs from human samples is crucial for a better understanding of their contribution to neuron/glial crosstalk and disease progression.
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Affiliation(s)
- Mikhail Melnik
- UCLA School of Nursing, Los Angeles, CA 90095, USA; Neuroscience Interdepartmental Program, UCLA School of Medicine, Los Angeles, CA 90095, USA
| | | | - Ricky Ma
- UCLA School of Nursing, Los Angeles, CA 90095, USA
| | - Maria Corrada
- Departments of Neurology, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, UC Irvine, Irvine, CA 92697, USA
| | - Claudia Kawas
- Departments of Neurology, Irvine, CA 92697, USA; Neurobiology & Behavior, Irvine, CA 92697, USA; Institute for Memory Impairments and Neurological Disorders, UC Irvine, Irvine, CA 92697, USA
| | - Ryan Bohannan
- Institute for Memory Impairments and Neurological Disorders, UC Irvine, Irvine, CA 92697, USA
| | - Chad Caraway
- Institute for Memory Impairments and Neurological Disorders, UC Irvine, Irvine, CA 92697, USA
| | | | - Jason D Hinman
- Mary S. Easton Center for Alzheimer's Research at UCLA, Los Angeles, CA 90073, USA; Departments of Neurology, UCLA School of Medicine, Los Angeles, CA 90095, USA
| | - Varghese John
- Mary S. Easton Center for Alzheimer's Research at UCLA, Los Angeles, CA 90073, USA; Departments of Neurology, UCLA School of Medicine, Los Angeles, CA 90095, USA
| | - Tina Bilousova
- UCLA School of Nursing, Los Angeles, CA 90095, USA; Mary S. Easton Center for Alzheimer's Research at UCLA, Los Angeles, CA 90073, USA; Departments of Neurology, UCLA School of Medicine, Los Angeles, CA 90095, USA.
| | - Karen H Gylys
- UCLA School of Nursing, Los Angeles, CA 90095, USA; Mary S. Easton Center for Alzheimer's Research at UCLA, Los Angeles, CA 90073, USA; Neuroscience Interdepartmental Program, UCLA School of Medicine, Los Angeles, CA 90095, USA
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Dashkova AS, Kovalev VI, Chaplygina AV, Zhdanova DY, Bobkova NV. Unique Properties of Synaptosomes and Prospects for Their Use for the Treatment of Alzheimer's Disease. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:1031-1044. [PMID: 38981699 DOI: 10.1134/s0006297924060051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 03/21/2024] [Accepted: 03/23/2024] [Indexed: 07/11/2024]
Abstract
Alzheimer's disease (AD) is a severe neurodegenerative condition affecting millions worldwide. Prevalence of AD correlates with increased life expectancy and aging population in the developed countries. Considering that AD is a multifactorial disease involving various pathological processes such as synaptic dysfunction, neuroinflammation, oxidative stress, and improper protein folding, a comprehensive approach targeting multiple pathways may prove effective in slowing the disease progression. Cellular therapy and its further development in the form of cell vesicle and particularly mitochondrial transplantation represent promising approaches for treating neurodegeneration. The use of synaptosomes, due to uniqueness of their contents, could mark a new stage in the development of comprehensive therapies for neurodegenerative diseases, particularly AD. Synaptosomes contain unique memory mitochondria, which differ not only in size but also in functionality compared to the mitochondria in the neuronal soma. These synaptosomal mitochondria actively participate in cellular communication and signal transmission within synapses. Synaptosomes also contain other elements such as their own protein synthesis machinery, synaptic vesicles with neurotransmitters, synaptic adhesion molecules, and microRNAs - all crucial for synaptic transmission and, consequently, cognitive processes. Complex molecular ensemble ensures maintenance of the synaptic autonomy of mitochondria. Additionally, synaptosomes, with their affinity for neurons, can serve as an optimal platform for targeted drug delivery to nerve cells. This review discusses unique composition of synaptosomes, their capabilities and advantages, as well as limitations of their suggested use as therapeutic agents for treating neurodegenerative pathologies, particularly AD.
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Affiliation(s)
- Alla S Dashkova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Vladimir I Kovalev
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Alina V Chaplygina
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Daria Yu Zhdanova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Natalia V Bobkova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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Hacioglu C, Kar F, Ozbayer C, Gundogdu AC. Ex vivo investigation of betaine and boric acid function as preprotective agents on rat synaptosomes to be treated with Aβ (1-42). ENVIRONMENTAL TOXICOLOGY 2024; 39:2138-2149. [PMID: 38108610 DOI: 10.1002/tox.24098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 08/31/2023] [Accepted: 12/01/2023] [Indexed: 12/19/2023]
Abstract
Recent evidence suggests that ferroptosis, an iron-dependent cell death process, may be involved in Alzheimer's disease (AD) pathology. The study evaluated the therapeutic potential of betaine and boric acid (BA) pretreatment administered to rats for 21 days in AD. Then, the rats were sacrificed, and morphological and biochemical analyses were performed in brain tissues. Next, an ex vivo AD model was created by applying amyloid-β (Aβ1-42) to synaptosomes isolated from the brain tissues. Synaptosomes were analyzed with micrograph images, and protein and mRNA levels of ferroptotic markers were determined. Betaine and BA pretreatments did not cause any morphological and biochemical differences in the brain tissue. However, Aβ (1-42) administration in synaptosomes increased the levels of acyl-CoA synthetase long chain family member-4 (ACSL4), transferrin receptor-1 protein (TfR1), malondialdehyde (MDA), and 8-hydroxydeoxyguanosine (8-OHdG) and decreased the levels glutathione peroxidase-4 (GPx4) and glutathione (GSH). Moreover, ACSL4, GPx4, and TfR1 mRNA and protein levels were similar to the ELISA results. In contrast, betaine and BA pretreatments decreased the levels of ACSL4, TfR1, MDA, and 8-OHdG in synaptosomes incubated with Aβ1-42, while promoting increased levels of GPx4 and GSH. In addition, betaine and BA pretreatments completely reversed ACSL4, GPx4, and TfR1 mRNA and protein levels. Therefore, betaine and BA pretreatments may contribute to the prevention of neurodegenerative damage by supporting antiferroptotic activities.
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Affiliation(s)
- Ceyhan Hacioglu
- Faculty of Pharmacy, Department of Biochemistry, Düzce University, Düzce, Turkey
- Faculty of Medicine, Department of Medical Biochemistry, Düzce University, Düzce, Turkey
| | - Fatih Kar
- Faculty of Medicine, Department of Medical Biochemistry, Kütahya Health Sciences University, Kütahya, Turkey
| | - Cansu Ozbayer
- Faculty of Medicine, Department of Medical Biology, Kütahya Health Sciences University, Kütahya, Turkey
| | - Ayse Cakir Gundogdu
- Faculty of Medicine Department of Histology and Embryology, Kütahya Health Sciences University, Kütahya, Turkey
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Ibrahim MJ, Baiju V, Sen S, Chandran PP, Ashraf GM, Haque S, Ahmad F. Utilities of Isolated Nerve Terminals in Ex Vivo Analyses of Protein Translation in (Patho)physiological Brain States: Focus on Alzheimer's Disease. Mol Neurobiol 2024; 61:91-103. [PMID: 37582987 DOI: 10.1007/s12035-023-03562-x] [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: 06/05/2023] [Accepted: 08/07/2023] [Indexed: 08/17/2023]
Abstract
Synapses are the cellular substrates of higher-order brain functions, and their dysfunction is an early and primary pathogenic mechanism across several neurological disorders. In particular, Alzheimer's disease (AD) is categorized by prodromal structural and functional synaptic deficits, prior to the advent of classical behavioral and pathological features. Recent research has shown that the development, maintenance, and plasticity of synapses depend on localized protein translation. Synaptosomes and synaptoneurosomes are biochemically isolated synaptic terminal preparations which have long been used to examine a variety of synaptic processes ex vivo in both healthy and pathological conditions. These ex vivo preparations preserve the mRNA species and the protein translational machinery. Hence, they are excellent in organello tools for the study of alterations in mRNA levels and protein translation in neuropathologies. Evaluation of synapse-specific basal and activity-driven de novo protein translation activity can be conveniently performed in synaptosomal/synaptoneurosomal preparations from both rodent and human brain tissue samples. This review gives a quick overview of the methods for isolating synaptosomes and synaptoneurosomes before discussing the studies that have utilized these preparations to study localized synapse-specific protein translation in (patho)physiological situations, with an emphasis on AD. While the review is not an exhaustive accumulation of all the studies evaluating synaptic protein translation using the synaptosomal model, the aim is to assemble the most relevant studies that have done so. The hope is to provide a suitable research platform to aid neuroscientists to utilize the synaptosomal/synaptoneurosomal models to evaluate the molecular mechanisms of synaptic dysfunction within the specific confines of mRNA localization and protein translation research.
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Affiliation(s)
- Mohammad Jasim Ibrahim
- Department of Biotechnology, Vellore Institute of Technology, Vellore, Tamil Nadu, India, 632014
| | - Viswanath Baiju
- Department of Biotechnology, Vellore Institute of Technology, Vellore, Tamil Nadu, India, 632014
| | - Shivam Sen
- Department of Biotechnology, Vellore Institute of Technology, Vellore, Tamil Nadu, India, 632014
| | - Pranav Prathapa Chandran
- Department of Biotechnology, Vellore Institute of Technology, Vellore, Tamil Nadu, India, 632014
| | - Ghulam Md Ashraf
- University of Sharjah, College of Health Sciences, and Research Institute for Medical and Health Sciences, Department of Medical Laboratory Sciences, University City, 27272, Sharjah, United Arab Emirates.
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, 45142, Jazan, Saudi Arabia
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Beirut, Lebanon
- Centre of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman, United Arab Emirates
| | - Faraz Ahmad
- Department of Biotechnology, Vellore Institute of Technology, Vellore, Tamil Nadu, India, 632014.
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Yang S, Park JH, Lu HC. Axonal energy metabolism, and the effects in aging and neurodegenerative diseases. Mol Neurodegener 2023; 18:49. [PMID: 37475056 PMCID: PMC10357692 DOI: 10.1186/s13024-023-00634-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/08/2023] [Indexed: 07/22/2023] Open
Abstract
Human studies consistently identify bioenergetic maladaptations in brains upon aging and neurodegenerative disorders of aging (NDAs), such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and Amyotrophic lateral sclerosis. Glucose is the major brain fuel and glucose hypometabolism has been observed in brain regions vulnerable to aging and NDAs. Many neurodegenerative susceptible regions are in the topological central hub of the brain connectome, linked by densely interconnected long-range axons. Axons, key components of the connectome, have high metabolic needs to support neurotransmission and other essential activities. Long-range axons are particularly vulnerable to injury, neurotoxin exposure, protein stress, lysosomal dysfunction, etc. Axonopathy is often an early sign of neurodegeneration. Recent studies ascribe axonal maintenance failures to local bioenergetic dysregulation. With this review, we aim to stimulate research in exploring metabolically oriented neuroprotection strategies to enhance or normalize bioenergetics in NDA models. Here we start by summarizing evidence from human patients and animal models to reveal the correlation between glucose hypometabolism and connectomic disintegration upon aging/NDAs. To encourage mechanistic investigations on how axonal bioenergetic dysregulation occurs during aging/NDAs, we first review the current literature on axonal bioenergetics in distinct axonal subdomains: axon initial segments, myelinated axonal segments, and axonal arbors harboring pre-synaptic boutons. In each subdomain, we focus on the organization, activity-dependent regulation of the bioenergetic system, and external glial support. Second, we review the mechanisms regulating axonal nicotinamide adenine dinucleotide (NAD+) homeostasis, an essential molecule for energy metabolism processes, including NAD+ biosynthetic, recycling, and consuming pathways. Third, we highlight the innate metabolic vulnerability of the brain connectome and discuss its perturbation during aging and NDAs. As axonal bioenergetic deficits are developing into NDAs, especially in asymptomatic phase, they are likely exaggerated further by impaired NAD+ homeostasis, the high energetic cost of neural network hyperactivity, and glial pathology. Future research in interrogating the causal relationship between metabolic vulnerability, axonopathy, amyloid/tau pathology, and cognitive decline will provide fundamental knowledge for developing therapeutic interventions.
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Affiliation(s)
- Sen Yang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Jung Hyun Park
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Hui-Chen Lu
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
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Hindley N, Sanchez Avila A, Henstridge C. Bringing synapses into focus: Recent advances in synaptic imaging and mass-spectrometry for studying synaptopathy. Front Synaptic Neurosci 2023; 15:1130198. [PMID: 37008679 PMCID: PMC10050382 DOI: 10.3389/fnsyn.2023.1130198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/28/2023] [Indexed: 03/17/2023] Open
Abstract
Synapses are integral for healthy brain function and are becoming increasingly recognized as key structures in the early stages of brain disease. Understanding the pathological processes driving synaptic dysfunction will unlock new therapeutic opportunities for some of the most devastating diseases of our time. To achieve this we need a solid repertoire of imaging and molecular tools to interrogate synaptic biology at greater resolution. Synapses have historically been examined in small numbers, using highly technical imaging modalities, or in bulk, using crude molecular approaches. However, recent advances in imaging techniques are allowing us to analyze large numbers of synapses, at single-synapse resolution. Furthermore, multiplexing is now achievable with some of these approaches, meaning we can examine multiple proteins at individual synapses in intact tissue. New molecular techniques now allow accurate quantification of proteins from isolated synapses. The development of increasingly sensitive mass-spectrometry equipment means we can now scan the synaptic molecular landscape almost in totality and see how this changes in disease. As we embrace these new technical developments, synapses will be viewed with clearer focus, and the field of synaptopathy will become richer with insightful and high-quality data. Here, we will discuss some of the ways in which synaptic interrogation is being facilitated by methodological advances, focusing on imaging, and mass spectrometry.
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Affiliation(s)
- Nicole Hindley
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- *Correspondence: Nicole Hindley,
| | - Anna Sanchez Avila
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- Euan Macdonald Centre for Motor Neuron Disease, University of Edinburgh, Edinburgh, United Kingdom
| | - Christopher Henstridge
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- Euan Macdonald Centre for Motor Neuron Disease, University of Edinburgh, Edinburgh, United Kingdom
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10
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Shah UJ, Alsulimani A, Ahmad F, Mathkor DM, Alsaieedi A, Harakeh S, Nasiruddin M, Haque S. Bioplatforms in liquid biopsy: advances in the techniques for isolation, characterization and clinical applications. Biotechnol Genet Eng Rev 2022; 38:339-383. [PMID: 35968863 DOI: 10.1080/02648725.2022.2108994] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Tissue biopsy analysis has conventionally been the gold standard for cancer prognosis, diagnosis and prediction of responses/resistances to treatments. The existing biopsy procedures used in clinical practice are, however, invasive, painful and often associated with pitfalls like poor recovery of tumor cells and infeasibility for repetition in single patients. To circumvent these limitations, alternative non-invasive, rapid and economical, yet sturdy, consistent and dependable, biopsy techniques are required. Liquid biopsy is an emerging technology that fulfills these criteria and potentially much more in terms of subject-specific real-time monitoring of cancer progression, determination of tumor heterogeneity and treatment responses, and specific identification of the type and stages of cancers. The present review first briefly revisits the state-of-the-art technique of liquid biopsy and then proceeds to address in detail, the advances in the potential clinical applications of four major biological agencies present in liquid biopsy samples (circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), exosomes and tumor-educated platelets (TEPs)). Finally, the authors conclude with the limitations that need to be addressed in order for liquid biopsy to effectively replace the conventional invasive biopsy methods in the clinical settings.
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Affiliation(s)
- Ushma Jaykamal Shah
- MedGenome Labs Ltd, Kailash Cancer Hospital and Research Center, Vadodara, India
| | - Ahmad Alsulimani
- Medical Laboratory Technology Department, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Faraz Ahmad
- Department of Biotechnology, School of Bio Sciences and Technology (SBST), Vellore Institute of Technology, Vellore, India
| | - Darin Mansor Mathkor
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
| | - Ahdab Alsaieedi
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Steve Harakeh
- King Fahd Medical Research Center, and Yousef Abdullatif Jameel Chair of Prophetic Medicine Application, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammad Nasiruddin
- MedGenome Labs Ltd, Narayana Health City, Bangalore, India.,Genomics Lab, Orbito Asia Diagnostics, Coimbatore, India
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
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11
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Yin X, Li Y, Fan X, Huang F, Qiu Y, Zhao C, Zhou Z, Gu Q, Xia L, Bao J, Wang X, Liu F, Qian W. SIRT1 deficiency increases O-GlcNAcylation of tau, mediating synaptic tauopathy. Mol Psychiatry 2022; 27:4323-4334. [PMID: 35879403 DOI: 10.1038/s41380-022-01689-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 02/07/2023]
Abstract
Hyperphosphorylation of the microtubule associated protein tau is associated with several neurodegenerative diseases including Alzheimer's Disease (AD), collectively referred to as tauopathies. However, the mechanisms by which tau is linked to synaptic dysfunction and memory impairment remain unclear. To address this question, we constructed a mouse model with brain-specific deficiency of SIRT1 (SIRT1 flox/Cre + ). Here, we show that increase of site-specific phosphorylation of tau is coupled with the strengthened O-GlcNAcylation of tau triggered by reduced O-GlcNAcase (OGA) and increased O-GlcNAc transferase (OGT) protein level in the brain of SIRT1 flox/Cre+ mice. SIRT1 deletion in mice brain changes the synaptosomal distribution of site-specific phospho-tau. Learning and memory deficiency induced by dendritic spine deficits and synaptic dysfunction are revealed via SIRT1 flox/Cre+ mice. Our results provide evidence for SIRT1 as a potential therapeutic target in clinical tauopathies.
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Affiliation(s)
- Xiaomin Yin
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Yuanyuan Li
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Xing Fan
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Fang Huang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry/ Hubei Province of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yanyan Qiu
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Chenhao Zhao
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Zheng Zhou
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Qun Gu
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Liye Xia
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Junze Bao
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Xiaochuan Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry/ Hubei Province of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Fei Liu
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, 10314, USA.
| | - Wei Qian
- Department of Biochemistry and Molecular Biology, School of Medicine, Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
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12
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Early Changes in Transcriptomic Profiles in Synaptodendrosomes Reveal Aberrant Synaptic Functions in Alzheimer’s Disease. Int J Mol Sci 2022; 23:ijms23168888. [PMID: 36012153 PMCID: PMC9408306 DOI: 10.3390/ijms23168888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/29/2022] [Accepted: 08/04/2022] [Indexed: 11/16/2022] Open
Abstract
Alzheimer’s disease (AD) is one of the most prevalent neurodegenerative disorders characterized by the progressive decline of cognitive functions, and is closely associated with the dysfunction of synapses, which comprise the basic structure that mediates the communication between neurons. Although the protein architecture and machinery for protein translation at synapses are extensively studied, the impact that local changes in the mRNA reservoir have on AD progression is largely unknown. Here, we investigated the changes in transcriptomic profiles in the synaptodendrosomes purified from the cortices of AD mice at ages 3 and 6 months, a stage when early signatures of synaptic dysfunction are revealed. The transcriptomic profiles of synaptodendrosomes showed a greater number of localized differentially expressed genes (DEGs) in 6-month-old AD mice compared with mice 3 months of age. Gene Ontology (GO) analysis showed that these DEGs are majorly enriched in mitochondrial biogenesis and metabolic activity. More specifically, we further identified three representative DEGs in mitochondrial and metabolic pathways—Prnp, Cst3, and Cox6c—that regulate the dendritic spine density and morphology in neurons. Taken together, this study provides insights into the transcriptomic changes in synaptodendrosomes during AD progression, which may facilitate the development of intervention strategies targeting local translation to ameliorate the pathological progression of AD.
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13
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Kumar S, Orlov E, Gowda P, Bose C, Swerdlow RH, Lahiri DK, Reddy PH. Synaptosome microRNAs regulate synapse functions in Alzheimer's disease. NPJ Genom Med 2022; 7:47. [PMID: 35941185 PMCID: PMC9359989 DOI: 10.1038/s41525-022-00319-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 07/15/2022] [Indexed: 01/05/2023] Open
Abstract
MicroRNAs (miRNAs) are found in nerve terminals, synaptic vesicles, and synaptosomes, but it is unclear whether synaptic and cytosolic miRNA populations differ in Alzheimer's disease (AD) or if synaptosomal miRNAs affect AD synapse activity. To address these questions, we generated synaptosomes and cytosolic fractions from postmortem brains of AD and unaffected control (UC) samples and analyzed them using a global Affymetrix miRNAs microarray platform. A group of miRNAs significantly differed (P < 0.0001) with high fold changes variance (+/- >200-fold) in their expressions in different comparisons: (1) UC synaptosome vs UC cytosol, (2) AD synaptosomes vs AD cytosol, (3) AD cytosol vs UC cytosol, and (4) AD synaptosomes vs UC synaptosomes. MiRNAs data analysis revealed that some potential miRNAs were consistently different across sample groups. These differentially expressed miRNAs were further validated using AD postmortem brains, brains of APP transgenic (Tg2576), Tau transgenic (P301L), and wild-type mice. The miR-501-3p, miR-502-3p, and miR-877-5p were identified as potential synaptosomal miRNAs upregulated with disease progression based on AD Braak stages. Gene Ontology Enrichment and Ingenuity Pathway Analysis of synaptosomal miRNAs showed the involvement of miRNAs in nervous system development, cell junction organization, synapse assembly formation, and function of GABAergic synapse. This is the first description of synaptic versus cytosolic miRNAs in AD and their significance in synapse function.
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Affiliation(s)
- Subodh Kumar
- grid.416992.10000 0001 2179 3554Center of Emphasis in Neuroscience, Department of Molecular and Translational Medicine, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905 USA ,grid.416992.10000 0001 2179 3554Internal Medicine Department, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430 USA ,grid.416992.10000 0001 2179 3554Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905, USA
| | - Erika Orlov
- grid.416992.10000 0001 2179 3554Internal Medicine Department, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430 USA
| | - Prashanth Gowda
- grid.416992.10000 0001 2179 3554Internal Medicine Department, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430 USA
| | - Chhanda Bose
- grid.416992.10000 0001 2179 3554Internal Medicine Department, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430 USA
| | - Russell H. Swerdlow
- grid.266515.30000 0001 2106 0692Department of Neurology, the University of Kansas Medical Center, University of Kansas Alzheimer’s Disease Research Center, Fairway, KS 66205 USA
| | - Debomoy K. Lahiri
- grid.257413.60000 0001 2287 3919Laboratory of Molecular Neurogenetics’ Departments of Psychiatry and Medical & Molecular Genetics, Indiana University School of Medicine’ Indiana Alzheimer’s Disease Research Center, Stark Neuroscience Research Institute, Indianapolis, IN 46202 USA
| | - P. Hemachandra Reddy
- grid.416992.10000 0001 2179 3554Internal Medicine Department, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430 USA ,grid.416992.10000 0001 2179 3554Department of Pharmacology & Neuroscience, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430 USA ,grid.416992.10000 0001 2179 3554Department of Neurology, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430 USA ,grid.416992.10000 0001 2179 3554Department of Public Health, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430 USA
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14
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Bhattacharya U, Jhou JF, Zou YF, Abrigo G, Lin SW, Chen YH, Chien FC, Tai HC. Surface charge manipulation and electrostatic immobilization of synaptosomes for super-resolution imaging: a study on tau compartmentalization. Sci Rep 2021; 11:18583. [PMID: 34545174 PMCID: PMC8452691 DOI: 10.1038/s41598-021-98142-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 07/30/2021] [Indexed: 12/31/2022] Open
Abstract
Synaptosomes are subcellular fractions prepared from brain tissues that are enriched in synaptic terminals, widely used for the study of neural transmission and synaptic dysfunction. Immunofluorescence imaging is increasingly applied to synaptosomes to investigate protein localization. However, conventional methods for imaging synaptosomes over glass coverslips suffer from formaldehyde-induced aggregation. Here, we developed a facile strategy to capture and image synaptosomes without aggregation artefacts. First, ethylene glycol bis(succinimidyl succinate) (EGS) is chosen as the chemical fixative to replace formaldehyde. EGS/glycine treatment makes the zeta potential of synaptosomes more negative. Second, we modified glass coverslips with 3-aminopropyltriethoxysilane (APTES) to impart positive charges. EGS-fixed synaptosomes spontaneously attach to modified glasses via electrostatic attraction while maintaining good dispersion. Individual synaptic terminals are imaged by conventional fluorescence microscopy or by super-resolution techniques such as direct stochastic optical reconstruction microscopy (dSTORM). We examined tau protein by two-color and three-color dSTORM to understand its spatial distribution within mouse cortical synapses, observing tau colocalization with synaptic vesicles as well postsynaptic densities.
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Affiliation(s)
| | - Jia-Fong Jhou
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
| | - Yi-Fong Zou
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
| | - Gerald Abrigo
- Department of Optics and Photonics, National Central University, Taoyuan, Taiwan
| | - Shu-Wei Lin
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
| | - Yun-Hsuan Chen
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
| | - Fan-Ching Chien
- Department of Optics and Photonics, National Central University, Taoyuan, Taiwan
| | - Hwan-Ching Tai
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan.
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15
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Behavioural Functions and Cerebral Blood Flow in a P301S Tauopathy Mouse Model: A Time-Course Study. Int J Mol Sci 2021; 22:ijms22189727. [PMID: 34575885 PMCID: PMC8468775 DOI: 10.3390/ijms22189727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/29/2021] [Accepted: 09/05/2021] [Indexed: 12/15/2022] Open
Abstract
Tauopathies refer to a group of neurodegenerative diseases with intracellular accumulation of hyperphosphorylated and aggregated microtubule-associated protein tau (MAPT) in neurons and glial cells. PS19 mice bearing the MAPT P301S mutation have been used to mimic human frontotemporal lobar degeneration. The present study was designed to systematically investigate how behavioural functions, resting cerebral blood flow (CBF) and tau pathology change in PS19 mice at 2, 4, 6, 8 and 12 months of age in a single study under one experimental condition, allowing for the cumulative assessment of age- and genotype-dependent changes. PS19 mice displayed hyperactivity and reduced anxiety levels with age, early and persistent spatial working memory deficits and reduced resting neocortical CBF. Immunoblotting and immunohistochemistry revealed age-related increases in phosphorylated tau in the brain of PS19 mice. In conclusion, the present study, for the first time, cumulatively demonstrated the time-course of changes in behavioural functions, resting CBF and tau pathology in a P301S tauopathy mouse model through their developmental span. This information provides further evidence for the utility of this model to study neurodegenerative events associated with tauopathy and tau dysfunction.
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16
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Chemical Stimulation of Rodent and Human Cortical Synaptosomes: Implications in Neurodegeneration. Cells 2021; 10:cells10051174. [PMID: 34065927 PMCID: PMC8151714 DOI: 10.3390/cells10051174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 04/29/2021] [Accepted: 05/09/2021] [Indexed: 12/14/2022] Open
Abstract
Synaptic plasticity events, including long-term potentiation (LTP), are often regarded as correlates of brain functions of memory and cognition. One of the central players in these plasticity-related phenomena is the α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor (AMPAR). Increased levels of AMPARs on postsynaptic membranes thus constitute a biochemical measure of LTP. Isolated synaptic terminals (synaptosomes) are an excellent ex vivo tool to monitor synaptic physiology in healthy and diseased brains, particularly in human research. We herein describe three protocols for chemically-induced LTP (cLTP) in synaptosomes from both rodent and human brain tissues. Two of these chemical stimulation protocols are described for the first time in synaptosomes. A pharmacological block of synaptosomal actin dynamics confirmed the efficiency of the cLTP protocols. Furthermore, the study prototypically evaluated the deficiency of cLTP in cortical synaptosomes obtained from human cases of early-onset Alzheimer’s disease (EOAD) and frontotemporal lobar degeneration (FLTD), as well as an animal model that mimics FLTD.
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17
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Morini R, Bizzotto M, Perrucci F, Filipello F, Matteoli M. Strategies and Tools for Studying Microglial-Mediated Synapse Elimination and Refinement. Front Immunol 2021; 12:640937. [PMID: 33708226 PMCID: PMC7940197 DOI: 10.3389/fimmu.2021.640937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 02/01/2021] [Indexed: 01/14/2023] Open
Abstract
The role of microglia in controlling synapse homeostasis is becoming increasingly recognized by the scientific community. In particular, the microglia-mediated elimination of supernumerary synapses during development lays the basis for the correct formation of neuronal circuits in adulthood, while the possible reactivation of this process in pathological conditions, such as schizophrenia or Alzheimer's Disease, provides a promising target for future therapeutic strategies. The methodological approaches to investigate microglial synaptic engulfment include different in vitro and in vivo settings. Basic in vitro assays, employing isolated microglia and microbeads, apoptotic membranes, liposomes or synaptosomes allow the quantification of the microglia phagocytic abilities, while co-cultures of microglia and neurons, deriving from either WT or genetically modified mice models, provide a relatively manageable setting to investigate the involvement of specific molecular pathways. Further detailed analysis in mice brain is then mandatory to validate the in vitro assays as representative for the in vivo situation. The present review aims to dissect the main technical approaches to investigate microglia-mediated phagocytosis of neuronal and synaptic substrates in critical developmental time windows.
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Affiliation(s)
- Raffaella Morini
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy
| | - Matteo Bizzotto
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy
| | - Fabio Perrucci
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy
| | - Fabia Filipello
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy.,Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States
| | - Michela Matteoli
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy.,Consiglio Nazionale Delle Ricerche (CNR), Institute of Neuroscience - URT Humanitas, Rozzano, Italy
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