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Sánchez-Fernández N, Gómez-Acero L, Castañé A, Adell A, Campa L, Bonaventura J, Brito V, Ginés S, Queiróz F, Silva H, Lopes JP, Lopes CR, Radošević M, Gasull X, Cunha RA, Köfalvi A, Ferreira SG, Ciruela F, Aso E. A combination of Δ 9-tetrahydrocannabinol and cannabidiol modulates glutamate dynamics in the hippocampus of an animal model of Alzheimer's disease. Neurotherapeutics 2024; 21:e00439. [PMID: 39232876 DOI: 10.1016/j.neurot.2024.e00439] [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: 04/25/2024] [Revised: 08/13/2024] [Accepted: 08/16/2024] [Indexed: 09/06/2024] Open
Abstract
A combination of Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) at non-psychoactive doses was previously demonstrated to reduce cognitive decline in APP/PS1 mice, an animal model of Alzheimer's disease (AD). However, the neurobiological substrates underlying these therapeutic properties of Δ9-THC and CBD are not fully understood. Considering that dysregulation of glutamatergic activity contributes to cognitive impairment in AD, the present study evaluates the hypothesis that the combination of these two natural cannabinoids might reverse the alterations in glutamate dynamics within the hippocampus of this animal model of AD. Interestingly, our findings reveal that chronic treatment with Δ9-THC and CBD, but not with any of them alone, reduces extracellular glutamate levels and the basal excitability of the hippocampus in APP/PS1 mice. These effects are not related to significant changes in the function and structure of glutamate synapses, as no relevant changes in synaptic plasticity, glutamate signaling or in the levels of key components of these synapses were observed in cannabinoid-treated mice. Our data instead indicate that these cannabinoid effects are associated with the control of glutamate uptake and/or to the regulation of the hippocampal network. Taken together, these results support the potential therapeutic properties of combining these natural cannabinoids against the excitotoxicity that occurs in AD brains.
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Affiliation(s)
- Nuria Sánchez-Fernández
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08907 L'Hospitalet de Llobregat, Spain; Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Laura Gómez-Acero
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08907 L'Hospitalet de Llobregat, Spain; Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Anna Castañé
- Institut d'Investigacions Biomèdiques de Barcelona (IIBB-CSIC), 08036 Barcelona, Spain; Department of Biomedicine, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08036 Barcelona, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), ISCIII, 28029 Madrid, Spain; Universitat de Vic-Universitat Central de Catalunya (UVic-UCC), Institut de Recerca i Innovació en Ciències de la Vida i de la Salut a la Catalunya Central (IRIS-CC), 08500 Vic, Spain
| | - Albert Adell
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), ISCIII, 28029 Madrid, Spain; Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Cantabria, 39011 Santander, Spain
| | - Leticia Campa
- Institut d'Investigacions Biomèdiques de Barcelona (IIBB-CSIC), 08036 Barcelona, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), ISCIII, 28029 Madrid, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Jordi Bonaventura
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08907 L'Hospitalet de Llobregat, Spain; Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Verónica Brito
- Department of Biomedicine, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08036 Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain; Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain
| | - Silvia Ginés
- Department of Biomedicine, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08036 Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain; Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain
| | - Francisco Queiróz
- CNC-Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Henrique Silva
- CNC-Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | - João Pedro Lopes
- CNC-Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Cátia R Lopes
- CNC-Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Marija Radošević
- Department of Biomedicine, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08036 Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Xavier Gasull
- Department of Biomedicine, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08036 Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; FMUC-Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Attila Köfalvi
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Samira G Ferreira
- CNC-Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Francisco Ciruela
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08907 L'Hospitalet de Llobregat, Spain; Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Ester Aso
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, School of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, 08907 L'Hospitalet de Llobregat, Spain; Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain.
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Jiang R, Li L, Wang B, Liu L, Liu L, Xian X, Li W. Ceftriaxone Modulates Ubiquitination of α-Amino-3-Hydroxy-5-Methyl-4-Isoxazole Propionic Acid Receptors to Improve Long-Term Potentiation Impairment Induced by Exogenous β-Amyloid in a Glutamate Transporter-1 Dependent Manner. Mol Neurobiol 2024; 61:7181-7194. [PMID: 38374316 DOI: 10.1007/s12035-024-04037-3] [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: 10/26/2023] [Accepted: 02/09/2024] [Indexed: 02/21/2024]
Abstract
Α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) are crucial for properties of synaptic plasticity, such as long-term potentiation (LTP). LTP impairment can occur early in the onset of Alzheimer's disease (AD). The downregulation or decreased abundance of AMPAR expression in the postsynaptic membrane is closely associated with LTP impairment. Ceftriaxone (Cef) can improve LTP impairment in the early stages of AD in a mouse model. The purpose of this study was to explore the mechanism underlying this process from the aspects of AMPAR expression and ubiquitination degree. In this study, we found that β-amyloid (Aβ) treatment induced hippocampal LTP impairment and AMPAR downregulation and ubiquitination. Cef pretreatment ameliorated Aβ-induced hippocampal LTP impairment, reduced AMPAR ubiquitination, and increased AMPAR expression, especially in the plasma membrane, in Aβ-treated mice. Administration of USP46 siRNA and DHK (a specific blocker of glutamate transporter-1) significantly inhibited the above effects of Cef, suggesting a role for anti-AMPAR ubiquitination and upregulation of glutamate transporter-1 (GLT-1) in the Cef-induced improvements mentioned above. The above findings demonstrate that pretreatment with Cef effectively mitigated Aβ-induced impairment of hippocampal LTP by suppressing the ubiquitination process of AMPARs in a GLT-1-dependent manner. These results provide novel insights into the underlying mechanisms elucidating the anti-AD by Cef.
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Affiliation(s)
- Rui Jiang
- Hebei Key Laboratory of Critical Disease Mechanism and Intervention, Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, People's Republic of China
- School of Nursing, Hebei Medical University, 309 Jianhua South Street, Shijiazhuang, 050000, People's Republic of China
| | - Li Li
- Central Laboratory, The Second Hospital of Hebei Medical University, 215 Heping West Road, Shijiazhuang, 050000, People's Republic of China
| | - Bu Wang
- Department of Emergency Critical Care Medicine, The Second Hospital of Hebei Medical University, 215 Heping West Road, Shijiazhuang, 050000, People's Republic of China
| | - Lizhe Liu
- Hebei Key Laboratory of Critical Disease Mechanism and Intervention, Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, People's Republic of China
| | - Lirong Liu
- Hebei Key Laboratory of Critical Disease Mechanism and Intervention, Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, People's Republic of China
| | - Xiaohui Xian
- Hebei Key Laboratory of Critical Disease Mechanism and Intervention, Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, People's Republic of China.
| | - Wenbin Li
- Hebei Key Laboratory of Critical Disease Mechanism and Intervention, Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, People's Republic of China.
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Guerrero-Carrasco M, Targett I, Olmos-Alonso A, Vargas-Caballero M, Gomez-Nicola D. Low-grade systemic inflammation stimulates microglial turnover and accelerates the onset of Alzheimer's-like pathology. Glia 2024; 72:1340-1355. [PMID: 38597386 DOI: 10.1002/glia.24532] [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: 12/07/2023] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/11/2024]
Abstract
Several in vivo studies have shown that systemic inflammation, mimicked by LPS, triggers an inflammatory response in the CNS, driven by microglia, characterized by an increase in inflammatory cytokines and associated sickness behavior. However, most studies induce relatively high systemic inflammation, not directly compared with the more common low-grade inflammatory events experienced in humans during the life course. Using mice, we investigated the effects of low-grade systemic inflammation during an otherwise healthy early life, and how this may precondition the onset and severity of Alzheimer's disease (AD)-like pathology. Our results indicate that low-grade systemic inflammation induces sub-threshold brain inflammation and promotes microglial proliferation driven by the CSF1R pathway, contrary to the effects caused by high systemic inflammation. In addition, repeated systemic challenges with low-grade LPS induce disease-associated microglia. Finally, using an inducible model of AD-like pathology (Line 102 mice), we observed that preconditioning with repeated doses of low-grade systemic inflammation, prior to APP induction, promotes a detrimental effect later in life, leading to an increase in Aβ accumulation and disease-associated microglia. These results support the notion that episodic low-grade systemic inflammation has the potential to influence the onset and severity of age-related neurological disorders, such as AD.
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Affiliation(s)
- Monica Guerrero-Carrasco
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Imogen Targett
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Adrian Olmos-Alonso
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Mariana Vargas-Caballero
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton, UK
- Institute for Life Sciences (IfLS), University of Southampton, Southampton, UK
| | - Diego Gomez-Nicola
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton, UK
- Institute for Life Sciences (IfLS), University of Southampton, Southampton, UK
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Zheng W, Li K, Zhong M, Wu K, Zhou L, Huang J, Liu L, Chen Z. Mitophagy activation by rapamycin enhances mitochondrial function and cognition in 5×FAD mice. Behav Brain Res 2024; 463:114889. [PMID: 38301932 DOI: 10.1016/j.bbr.2024.114889] [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: 11/03/2023] [Revised: 01/20/2024] [Accepted: 01/29/2024] [Indexed: 02/03/2024]
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by severe mitochondrial dysfunction, which is an intracellular process that is significantly compromised in the early stages of AD. Mitophagy, the selective removal of damaged mitochondria, is a potential therapeutic strategy for AD. Rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, augmented autophagy and mitigated cognitive impairment. Our study revealed that rapamycin enhances cognitive function by activating mitophagy, alleviating neuronal loss, and improving mitochondrial dysfunction in 5 ×FAD mice. Interestingly, the neuroprotective effect of rapamycin in AD were negated by treatment with 3-MA, a mitophagy inhibitor. Overall, our findings suggest that rapamycin ameliorates cognitive impairment in 5 ×FAD mice via mitophagy activation and its downstream PINK1-Parkin pathway, which aids in the clearance of amyloid-β (Aβ) and damaged mitochondria. This study reveals a novel mechanism involving mitophagy regulation underlying the therapeutic effect of rapamycin in AD. This study provides new insights and therapeutic targets for rapamycin in the treatment of AD. However, there are still some shortcomings in this topic; if we can further knock out the PINK1/Parkin gene in animals or use siRNA technology, we can further confirm the experimental results.
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Affiliation(s)
- Wenrong Zheng
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Kualiang Li
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China; Fujian Institute of Microbiology, Fuzhou 350007, China
| | - Meihua Zhong
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Kejun Wu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Lele Zhou
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Jie Huang
- Fujian Institute of Microbiology, Fuzhou 350007, China
| | - Libin Liu
- Department of Endocrinology and Metabolism, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Zhou Chen
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China.
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Lopes CR, Silva AC, Silva HB, Canas PM, Agostinho P, Cunha RA, Lopes JP. Adenosine A 2A Receptor Up-Regulation Pre-Dates Deficits of Synaptic Plasticity and of Memory in Mice Exposed to Aβ 1-42 to Model Early Alzheimer's Disease. Biomolecules 2023; 13:1173. [PMID: 37627238 PMCID: PMC10452250 DOI: 10.3390/biom13081173] [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: 06/16/2023] [Revised: 07/19/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
The intracerebroventricular (icv) injection of amyloid peptides (Aβ) models Alzheimer's disease (AD) in mice, as typified by the onset within 15 days of deficits of memory and of hippocampal long-term potentiation (LTP) that are prevented by the blockade of adenosine A2A receptors (A2AR). Since A2AR overfunction is sufficient to trigger memory deficits, we tested if A2AR were upregulated in hippocampal synapses before the onset of memory deficits to support the hypothesis that A2AR overfunction could be a trigger of AD. Six to eight days after Aβ-icv injection, mice displayed no alterations of hippocampal dependent memory; however, they presented an increased excitability of hippocampal synapses, a slight increase in LTP magnitude in Schaffer fiber-CA1 pyramid synapses and an increased density of A2AR in hippocampal synapses. A2AR blockade with SCH58261 (50 nM) normalized excitability and LTP in hippocampal slices from mice sacrificed 7-8 days after Aβ-icv injection. Fifteen days after Aβ-icv injection, mice displayed evident deficits of hippocampal-dependent memory deterioration, with reduced hippocampal CA1 LTP but no hyperexcitability and a sustained increase in synaptic A2AR, which blockade restored LTP magnitude. This shows that the upregulation of synaptic A2AR precedes the onset of deterioration of memory and of hippocampal synaptic plasticity, supporting the hypothesis that the overfunction of synaptic A2AR could be a trigger of memory deterioration in AD.
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Affiliation(s)
- Cátia R. Lopes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (C.R.L.); (A.C.S.); (H.B.S.); (P.M.C.); (P.A.); (J.P.L.)
- Faculty of Medicine, University of Coimbra, 3000-370 Coimbra, Portugal
| | - António C. Silva
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (C.R.L.); (A.C.S.); (H.B.S.); (P.M.C.); (P.A.); (J.P.L.)
| | - Henrique B. Silva
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (C.R.L.); (A.C.S.); (H.B.S.); (P.M.C.); (P.A.); (J.P.L.)
| | - Paula M. Canas
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (C.R.L.); (A.C.S.); (H.B.S.); (P.M.C.); (P.A.); (J.P.L.)
| | - Paula Agostinho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (C.R.L.); (A.C.S.); (H.B.S.); (P.M.C.); (P.A.); (J.P.L.)
- Faculty of Medicine, University of Coimbra, 3000-370 Coimbra, Portugal
| | - Rodrigo A. Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (C.R.L.); (A.C.S.); (H.B.S.); (P.M.C.); (P.A.); (J.P.L.)
- Faculty of Medicine, University of Coimbra, 3000-370 Coimbra, Portugal
| | - João Pedro Lopes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; (C.R.L.); (A.C.S.); (H.B.S.); (P.M.C.); (P.A.); (J.P.L.)
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Balietti M, Casoli T, Giorgetti B, Colangeli R, Nicoletti C, Solazzi M, Pugliese A, Conti F. Generation and Characterization of the First Murine Model of Alzheimer's Disease with Mutated AβPP Inserted in a BALB/c Background (C.B6/J-APPswe). J Alzheimers Dis 2023:JAD230195. [PMID: 37182890 DOI: 10.3233/jad-230195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
BACKGROUND Numerous mouse models of Alzheimer's disease (AD) are available, but all suffer from certain limitations, thus prompting further attempts. To date, no one model exists with amyloidopathy in a BALB/c strain. OBJECTIVE To generate and characterize the C.B6/J-APPswe mouse, a model of AD with a mutated human gene for the amyloid-β protein precursor (AβPP) inserted in a BALB/c background. METHODS We analyzed five groups at different ages (3, 6, 9, 12, and 16-18 months) of C.B6/J-APPswe and wild-type mice (50% males and 50% females) for the main hallmarks of AD by western blotting, amyloid-β (Aβ) ELISA, immunocytochemistry, electrophysiology, and behavioral tests. RESULTS The C.B6/J-APPswe mouse displays early AβPP and Aβ production, late amyloid plaques formation, high level of tau phosphorylation, synaptic deficits (reduced density and functional impairment due to a reduced post-synaptic responsiveness), neurodegeneration caused by apoptosis and necroptosis/necrosis, microgliosis, astrocytic abnormalities, and sex-related differences in explorative behavior, anxiety-like behavior, and spatial long-term and working memories. Social housing is feasible despite the intra-cage aggressiveness of male animals. CONCLUSION C.B6/J-APPswe mice develop most of the distinctive features of AD and is a suitable model for the study of brain atrophy mechanisms and of the differences between males and females in the onset of cognitive/non-cognitive deficits.
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Affiliation(s)
- Marta Balietti
- Center for Neurobiology of Aging, IRCCS INRCA, Ancona, Italy
| | - Tiziana Casoli
- Center for Neurobiology of Aging, IRCCS INRCA, Ancona, Italy
| | | | - Roberto Colangeli
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Cristina Nicoletti
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Moreno Solazzi
- Center for Neurobiology of Aging, IRCCS INRCA, Ancona, Italy
| | - Arianna Pugliese
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
| | - Fiorenzo Conti
- Center for Neurobiology of Aging, IRCCS INRCA, Ancona, Italy
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
- Fondazione di Medicina Molecolare e Terapia Cellulare, Università Politecnica delle Marche, Ancona, Italy
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Zhu D, Huang Y, Guo S, Li N, Yang X, Sui A, Wu Q, Zhang Y, Kong Y, Li Q, Zhang T, Zheng W, Li A, Yu J, Ma T, Li S. AQP4 Aggravates Cognitive Impairment in Sepsis-Associated Encephalopathy through Inhibiting Na v 1.6-Mediated Astrocyte Autophagy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205862. [PMID: 36922751 PMCID: PMC10190498 DOI: 10.1002/advs.202205862] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 02/24/2023] [Indexed: 05/18/2023]
Abstract
The pathology of sepsis-associated encephalopathy (SAE) is related to astrocyte-inflammation associated with aquaporin-4 (AQP4). The aim here is to investigate the effects of AQP4 associated with SAE and reveal its underlying mechanism causing cognitive impairment. The in vivo experimental results reveal that AQP4 in peripheral blood of patients with SAE is up-regulated, also the cortical and hippocampal tissue of cecal ligation and perforation (CLP) mouse brain has significant rise in AQP4. Furthermore, the data suggest that AQP4 deletion could attenuate learning and memory impairment, attributing to activation of astrocytic autophagy, inactivation of astrocyte and downregulate the expression of proinflammatory cytokines induced by CLP or lipopolysaccharide (LPS). Furthermore, the activation effect of AQP4 knockout on CLP or LPS-induced PPAR-γ inhibiting in astrocyte is related to intracellular Ca2+ level and sodium channel activity. Learning and memory impairment in SAE mouse model are attenuated by AQP4 knockout through activating autophagy, inhibiting neuroinflammation leading to neuroprotection via down-regulation of Nav 1.6 channels in the astrocytes. This results in the reduction of Ca2+ accumulation in the cell cytosol furthermore activating the inhibition of PPAR-γ signal transduction pathway in astrocytes.
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Affiliation(s)
- Dan‐Dan Zhu
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
- Department of Critical Care Medicinethe Second Hospital of Dalian Medical UniversityDalian116023China
| | - Yue‐Lin Huang
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Song‐Yu Guo
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Na Li
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Xue‐Wei Yang
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Ao‐Ran Sui
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Qiong Wu
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Yue Zhang
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Yue Kong
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Qi‐Fa Li
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Ting Zhang
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Wen‐Fei Zheng
- Department of Critical Care Medicinethe Second Hospital of Dalian Medical UniversityDalian116023China
| | - Ai‐Ping Li
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
| | - Jian Yu
- Department of Critical Care Medicinethe Second Hospital of Dalian Medical UniversityDalian116023China
| | - Tong‐Hui Ma
- School of MedicineNanjing University of Chinese MedicineNanjing210023China
| | - Shao Li
- Department of PhysiologyCollege of Basic Medical SciencesLiaoning Provincial Key Laboratory of Cerebral DiseasesNational‐Local Joint Engineering Research Center for Drug‐Research and Development (R & D) of Neurodegenerative DiseasesDalian Medical UniversityDalian116044China
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8
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Steinke I, Govindarajulu M, Pinky PD, Bloemer J, Yoo S, Ward T, Schaedig T, Young T, Wibowo FS, Suppiramaniam V, Amin RH. Selective PPAR-Delta/PPAR-Gamma Activation Improves Cognition in a Model of Alzheimer's Disease. Cells 2023; 12:1116. [PMID: 37190025 PMCID: PMC10136457 DOI: 10.3390/cells12081116] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/23/2023] [Accepted: 04/04/2023] [Indexed: 05/17/2023] Open
Abstract
Background: The continuously increasing association of Alzheimer's disease (AD) with increased mortality rates indicates an unmet medical need and the critical need for establishing novel molecular targets for therapeutic potential. Agonists for peroxisomal proliferator activating receptors (PPAR) are known to regulate energy in the body and have shown positive effects against Alzheimer's disease. There are three members of this class (delta, gamma, and alpha), with PPAR-gamma being the most studied, as these pharmaceutical agonists offer promise for AD because they reduce amyloid beta and tau pathologies, display anti-inflammatory properties, and improve cognition. However, they display poor brain bioavailability and are associated with several adverse side effects on human health, thus limiting their clinical application. Methods: We have developed a novel series of PPAR-delta and PPAR-gamma agonists in silico with AU9 as our lead compound that displays selective amino acid interactions focused upon avoiding the Tyr-473 epitope in the PPAR-gamma AF2 ligand binding domain. Results: This design helps to avoid the unwanted side effects of current PPAR-gamma agonists and improve behavioral deficits and synaptic plasticity while reducing amyloid-beta levels and inflammation in 3xTgAD animals. Conclusions: Our innovative in silico design of PPAR-delta/gamma agonists may offer new perspectives for this class of agonists for AD.
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Affiliation(s)
- Ian Steinke
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
| | - Manoj Govindarajulu
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
| | - Priyanka Das Pinky
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
| | - Jenna Bloemer
- Department of Pharmaceutical and Biomedical Sciences, Touro College of Pharmacy, New York, NY 10027, USA
| | - Sieun Yoo
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
| | - Tracey Ward
- Department of Pharmaceutical Sciences, Ferris State University, Big Rapids, MI 49307, USA
| | - Taylor Schaedig
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
| | - Taylor Young
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
| | - Fajar Setyo Wibowo
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
| | - Vishnu Suppiramaniam
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
- College of Science and Mathematics, Kennesaw State University, Kennesaw, GA 31044, USA
| | - Rajesh H. Amin
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36879, USA
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9
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Biasetti L, Rey S, Fowler M, Ratnayaka A, Fennell K, Smith C, Marshall K, Hall C, Vargas-Caballero M, Serpell L, Staras K. Elevated amyloid beta disrupts the nanoscale organization and function of synaptic vesicle pools in hippocampal neurons. Cereb Cortex 2023; 33:1263-1276. [PMID: 35368053 PMCID: PMC9930632 DOI: 10.1093/cercor/bhac134] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 02/02/2022] [Accepted: 03/07/2022] [Indexed: 11/14/2022] Open
Abstract
Alzheimer's disease is linked to increased levels of amyloid beta (Aβ) in the brain, but the mechanisms underlying neuronal dysfunction and neurodegeneration remain enigmatic. Here, we investigate whether organizational characteristics of functional presynaptic vesicle pools, key determinants of information transmission in the central nervous system, are targets for elevated Aβ. Using an optical readout method in cultured hippocampal neurons, we show that acute Aβ42 treatment significantly enlarges the fraction of functional vesicles at individual terminals. We observe the same effect in a chronically elevated Aβ transgenic model (APPSw,Ind) using an ultrastructure-function approach that provides detailed information on nanoscale vesicle pool positioning. Strikingly, elevated Aβ is correlated with excessive accumulation of recycled vesicles near putative endocytic sites, which is consistent with deficits in vesicle retrieval pathways. Using the glutamate reporter, iGluSnFR, we show that there are parallel functional consequences, where ongoing information signaling capacity is constrained. Treatment with levetiracetam, an antiepileptic that dampens synaptic hyperactivity, partially rescues these transmission defects. Our findings implicate organizational and dynamic features of functional vesicle pools as targets in Aβ-driven synaptic impairment, suggesting that interventions to relieve the overloading of vesicle retrieval pathways might have promising therapeutic value.
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Affiliation(s)
- Luca Biasetti
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Stephanie Rey
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
- National Physical Laboratory, Middlesex, TW11 0LW, United Kingdom
| | - Milena Fowler
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Arjuna Ratnayaka
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
- Faculty of Medicine, University of Southampton, SO17 1BJ, United Kingdom
| | - Kate Fennell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Catherine Smith
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Karen Marshall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Catherine Hall
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton, BN1 9QH, United Kingdom
| | - Mariana Vargas-Caballero
- School of Biological Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom
| | - Louise Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Kevin Staras
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
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10
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Ben-Nejma IRH, Keliris AJ, Vanreusel V, Ponsaerts P, Van der Linden A, Keliris GA. Altered dynamics of glymphatic flow in a mature-onset Tet-off APP mouse model of amyloidosis. Alzheimers Res Ther 2023; 15:23. [PMID: 36707887 PMCID: PMC9883946 DOI: 10.1186/s13195-023-01175-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 01/18/2023] [Indexed: 01/29/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is an incurable neurodegenerative disorder characterised by the progressive buildup of toxic amyloid-beta (Aβ) and tau protein aggregates eventually leading to cognitive decline. Recent lines of evidence suggest that an impairment of the glymphatic system (GS), a brain waste clearance pathway, plays a key role in the pathology of AD. Moreover, a relationship between GS function and neuronal network integrity has been strongly implicated. Here, we sought to assess the efficacy of the GS in a transgenic Tet-Off APP mouse model of amyloidosis, in which the expression of mutant APP was delayed until maturity, mimicking features of late-onset AD-the most common form of dementia in humans. METHODS To evaluate GS function, we used dynamic contrast-enhanced MRI (DCE-MRI) in 14-month-old Tet-Off APP (AD) mice and aged-matched littermate controls. Brain-wide transport of the Gd-DOTA contrast agent was monitored over time after cisterna magna injection. Region-of-interest analysis and computational modelling were used to assess GS dynamics while characterisation of brain tissue abnormalities at the microscale was performed ex vivo by immunohistochemistry. RESULTS We observed reduced rostral glymphatic flow and higher accumulation of the contrast agent in areas proximal to the injection side in the AD group. Clustering and subsequent computational modelling of voxel time courses revealed significantly lower influx time constants in AD relative to the controls. Ex vivo evaluation showed abundant amyloid plaque burden in the AD group coinciding with extensive astrogliosis and microgliosis. The neuroinflammatory responses were also found in plaque-devoid regions, potentially impacting brain-fluid circulation. CONCLUSIONS In a context resembling late-onset AD in humans, we demonstrate the disruption of glymphatic function and particularly a reduction in brain-fluid influx in the AD group. We conjecture that the hindered circulation of cerebrospinal fluid is potentially caused by wide-spread astrogliosis and amyloid-related obstruction of the normal routes of glymphatic flow resulting in redirection towards caudal regions. In sum, our study highlights the translational potential of alternative approaches, such as targeting brain-fluid circulation as potential therapeutic strategies for AD.
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Affiliation(s)
- Inès R. H. Ben-Nejma
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium
| | - Aneta J. Keliris
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium
| | - Verdi Vanreusel
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium ,Research in Dosimetric Applications, SCK CEN, Boeretang 200, Mol, 2400 Antwerp, Belgium
| | - Peter Ponsaerts
- grid.5284.b0000 0001 0790 3681Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium
| | - Annemie Van der Linden
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Georgios A. Keliris
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium ,grid.4834.b0000 0004 0635 685XInstitute of Computer Science, Foundation for Research and Technology – Hellas (FORTH), Heraklion, Crete Greece
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11
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McKee CG, Hoffos M, Vecchiarelli HA, Tremblay MÈ. Microglia: A pharmacological target for the treatment of age-related cognitive decline and Alzheimer's disease. Front Pharmacol 2023; 14:1125982. [PMID: 36969855 PMCID: PMC10034122 DOI: 10.3389/fphar.2023.1125982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 02/03/2023] [Indexed: 03/29/2023] Open
Abstract
As individuals age, microglia, the resident immune cells of the central nervous system (CNS), become less effective at preserving brain circuits. Increases in microglial inflammatory activity are thought to contribute to age-related declines in cognitive functions and to transitions toward mild cognitive impairment (MCI) and Alzheimer's disease (AD). As microglia possess receptors for communicating with the CNS environment, pharmacological therapies targeting these pathways hold potential for promoting homeostatic microglial functions within the aging CNS. Preclinical and early phase clinical trials investigating the therapeutic effects of pharmacological agents acting on microglia, including reactive oxygen species, TREM2, fractalkine signaling, the complement cascade, and the NLRP3 inflammasome, are currently underway; however, important questions remain unanswered. Current challenges include target selectivity, as many of the signaling pathways are expressed in other cell types. Furthermore, microglia are a heterogenous cell population with transcriptomic, proteomic, and microscopy studies revealing distinct microglial states, whose activities and abundance shift across the lifespan. For example, homeostatic microglia can transform into pathological states characterized by markers of oxidative stress. Selective pharmacological targeting aimed at limiting transitions to pathological states or promoting homeostatic or protective states, could help to avoid potentially harmful off-target effects on beneficial states or other cell types. In this mini-review we cover current microglial pathways of interest for the prevention and treatment of age-related cognitive decline and CNS disorders of aging focusing on MCI and AD. We also discuss the heterogeneity of microglia described in these conditions and how pharmacological agents could target specific microglial states.
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Affiliation(s)
- Chloe G. McKee
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Biology, University of Victoria, Victoria, BC, Canada
| | - Madison Hoffos
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Biology, University of Victoria, Victoria, BC, Canada
| | | | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Département de Médecine Moléculaire, Université Laval, Québec City, QC, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada
- Institute for Aging and Lifelong Health, University of Victoria, Victoria, BC, Canada
- *Correspondence: Marie-Ève Tremblay,
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12
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Viney TJ, Sarkany B, Ozdemir AT, Hartwich K, Schweimer J, Bannerman D, Somogyi P. Spread of pathological human Tau from neurons to oligodendrocytes and loss of high-firing pyramidal neurons in aging mice. Cell Rep 2022; 41:111646. [PMID: 36384116 PMCID: PMC9681663 DOI: 10.1016/j.celrep.2022.111646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 08/23/2022] [Accepted: 10/20/2022] [Indexed: 11/18/2022] Open
Abstract
Intracellular aggregation of hyperphosphorylated Tau (pTau) in the brain is associated with cognitive and motor impairments, and ultimately neurodegeneration. We investigate how human pTau affects cells and network activity in the hippocampal formation of the THY-Tau22 tauopathy model mice in vivo. We find that pTau preferentially accumulates in deep-layer pyramidal neurons, leading to neurodegeneration, and we establish that pTau spreads to oligodendrocytes. During goal-directed virtual navigation in aged transgenic mice, we detect fewer high-firing prosubicular pyramidal cells, but the firing population retains its coupling to theta oscillations. Analysis of network oscillations and firing patterns of pyramidal and GABAergic neurons recorded in head-fixed and freely moving mice suggests preserved neuronal coordination. In spatial memory tests, transgenic mice have reduced short-term familiarity, but spatial working and reference memory are surprisingly normal. We hypothesize that unimpaired subcortical network mechanisms maintain cortical neuronal coordination, counteracting the widespread pTau aggregation, loss of high-firing cells, and neurodegeneration.
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Affiliation(s)
- Tim J Viney
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK.
| | - Barbara Sarkany
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - A Tugrul Ozdemir
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Katja Hartwich
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Judith Schweimer
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - David Bannerman
- Department of Experimental Psychology, University of Oxford, Oxford OX2 6GG, UK
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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13
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Vargas-Caballero M, Warming H, Walker R, Holmes C, Cruickshank G, Patel B. Vagus Nerve Stimulation as a Potential Therapy in Early Alzheimer's Disease: A Review. Front Hum Neurosci 2022; 16:866434. [PMID: 35572001 PMCID: PMC9098960 DOI: 10.3389/fnhum.2022.866434] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/06/2022] [Indexed: 12/13/2022] Open
Abstract
Cognitive dysfunction in Alzheimer's disease (AD) is caused by disturbances in neuronal circuits of the brain underpinned by synapse loss, neuronal dysfunction and neuronal death. Amyloid beta and tau protein cause these pathological changes and enhance neuroinflammation, which in turn modifies disease progression and severity. Vagal nerve stimulation (VNS), via activation of the locus coeruleus (LC), results in the release of catecholamines in the hippocampus and neocortex, which can enhance synaptic plasticity and reduce inflammatory signalling. Vagal nerve stimulation has shown promise to enhance cognitive ability in animal models. Research in rodents has shown that VNS can have positive effects on basal synaptic function and synaptic plasticity, tune inflammatory signalling, and limit the accumulation of amyloid plaques. Research in humans with invasive and non-invasive VNS devices has shown promise for the modulation of cognition. However, the direct stimulation of the vagus nerve afforded with the invasive procedure carries surgical risks. In contrast, non-invasive VNS has the potential to be a broadly available therapy to manage cognitive symptoms in early AD, however, the magnitude and specificity of its effects remains to be elucidated, and the non-inferiority of the effects of non-invasive VNS as compared with invasive VNS still needs to be established. Ongoing clinical trials with healthy individuals and patients with early AD will provide valuable information to clarify the potential benefits of non-invasive VNS in cognition and AD. Whether invasive or non-invasive VNS can produce a significant improvement on memory function and whether its effects can modify the progression of AD will require further investigation.
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Affiliation(s)
| | - Hannah Warming
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Robert Walker
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Clive Holmes
- Memory Assessment and Research Centre, Southern Health Foundation Trust, Southampton, United Kingdom
| | - Garth Cruickshank
- Queen Elizabeth Hospital Birmingham, University of Birmingham, Birmingham, United Kingdom
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14
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Shipton OA, Tang CS, Paulsen O, Vargas-Caballero M. Differential vulnerability of hippocampal CA3-CA1 synapses to Aβ. Acta Neuropathol Commun 2022; 10:45. [PMID: 35379353 PMCID: PMC8981624 DOI: 10.1186/s40478-022-01350-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/18/2022] [Indexed: 11/25/2022] Open
Abstract
Amyloid-beta (Aβ) and tau protein are both involved in the pathogenesis of Alzheimer’s disease. Aβ produces synaptic deficits in wild-type mice that are not seen in Mapt−/− mice, suggesting that tau protein is required for these effects of Aβ. However, whether some synapses are more selectively affected and what factors may determine synaptic vulnerability to Aβ are poorly understood. Here we first observed that burst timing-dependent long-term potentiation (b-LTP) in hippocampal CA3-CA1 synapses, which requires GluN2B subunit-containing NMDA receptors (NMDARs), was inhibited by human Aβ1–42 (hAβ) in wild-type (WT) mice, but not in tau-knockout (Mapt−/−) mice. We then tested whether NMDAR currents were affected by hAβ; we found that hAβ reduced the postsynaptic NMDAR current in WT mice but not in Mapt−/− mice, while the NMDAR current was reduced to a similar extent by the GluN2B-selective NMDAR antagonist Ro 25–6981. To further investigate a possible difference in GluN2B-containing NMDARs in Mapt−/− mice, we used optogenetics to compare NMDAR/AMPAR ratio of EPSCs in CA1 synapses with input from left vs right CA3. It was previously reported in WT mice that hippocampal synapses in CA1 that receive input from the left CA3 display a higher NMDAR charge transfer and a higher Ro-sensitivity than synapses in CA1 that receive input from the right CA3. Here we observed the same pattern in Mapt−/− mice, thus differential NMDAR subunit expression does not explain the difference in hAβ effect on LTP. Finally, we asked whether synapses with left vs right CA3 input are differentially affected by hAβ in WT mice. We found that NMDAR current in synapses with input from the left CA3 were reduced while synapses with input from the right CA3 were unaffected by acute hAβ exposure. These results suggest that hippocampal CA3-CA1 synapses with presynaptic axon originating in the left CA3 are selectively vulnerable to Aβ and that a genetic knock out of tau protein protects them from Aβ synaptotoxicity.
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15
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You Q, Wang W, Tao T, Wang T, Zhang D, Wang L. miR-129 Regulates Cell Viability in Alzheimer’s Disease Through Targeting Amyloid Precursor Protein (APP). J BIOMATER TISS ENG 2022. [DOI: 10.1166/jbt.2022.2959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study intends to explore miR-129’s effect on cell viability of Alzheimer’s disease by regulating the target gene APP. The hippocampal neurons were assigned into model group (MO group); mimetic group (SI group); inhibitor group (IN group) followed by analysis of hippocampal
neuronal cell proliferation and activity, APP protein content, miR-129 expression and cell apoptosis by CCK-8 assay, Western blot method, MTT assay, qRT-PCR and flow cytometry. miR-129 expression of hippocampal neurons in IN group was lowest. Compared with IN and MO groups, SI group had significantly
increased miR-129 level and reduced number of hippocampal neuron apoptosis (P < 0.05). Compared with IN group, MO group had significantly reduced cell apoptosis (P < 0.05). SI group had highest number of hippocampal neurons proliferation followed by IN group. SI group had
highest OD value followed by MO group and IN group. The cell activity of SI group was higher than that of IN group and MO group (both P < 0.05). Compared with SI group, rat neuron activity in MO group was significantly higher than IN group (P < 0.05). The APP protein expression
of hippocampal neuron cells in SI group was lowest followed by MO group and IN group (P < 0.05). In conclusion, the low miR-129 expression can inhibit the activity of hippocampal neurons possibly through up-regulation of APP protein content.
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Affiliation(s)
- Qunwei You
- Department of Neurology, Taizhou First People’s Hospital, Taizhou City, Zhejiang Province, 318001, China
| | - Wenjie Wang
- Department of Neurology, Taizhou Central Hospital (Taizhou University Hospital), Taizhou City, Zhejiang Province, 318001, China
| | - Taotao Tao
- Department of Neurology, Taizhou Central Hospital (Taizhou University Hospital), Taizhou City, Zhejiang Province, 318001, China
| | - Tianyu Wang
- Department of Neurology, Taizhou Central Hospital (Taizhou University Hospital), Taizhou City, Zhejiang Province, 318001, China
| | - Danhong Zhang
- Department of Neurology, Taizhou Central Hospital (Taizhou University Hospital), Taizhou City, Zhejiang Province, 318001, China
| | - Liaojun Wang
- Department of Neurology, Taizhou Municipal Hospital, Taizhou City, Zhejiang Province, 317099, China
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Fang SC, Wang JJ, Chen F, Tang SS, Mu RH, Yuan DH, Zhao JJ, Hong H, Long Y. Hippocampal CysLT1R overexpression or activation accelerates memory deficits, synaptic dysfunction, and amyloidogenesis in young APP/PS1 transgenic mice. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1531. [PMID: 34790737 PMCID: PMC8576703 DOI: 10.21037/atm-21-4518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/02/2021] [Indexed: 11/12/2022]
Abstract
Background Our previous studies demonstrated that cysteinyl leukotrienes receptor 1 (CysLT1R) knockout, pharmacological blockade, or hippocampus knockdown produced beneficial effects against Alzheimer’s disease (AD); however, whether CysLT1R upregulation has deleterious effects on AD remains elusive. Methods In this study, we investigated the changes in behaviors, hippocampal amyloidogenesis, and synapse plasticity after CysLT1R overexpression by microinfusion of the lentiviral vector, containing its coding sequence of mouse (LV-CysLT1R), into the bilateral dentate gyri (DG) of the hippocampus or CysLT1R activation by repeated systemic administration of its agonist YM-17690 (0.1 mg/kg, once a day, i.p., for 28 d). Results The behavior data showed that overexpression of CysLT1R in hippocampal DG or administration of YM-17690 deteriorated behavioral performance in Morris water maze (MWM), Y-maze tests, and novel object recognition (NOR) in young APP/PS1 mice. The further studies showed that these treatments significantly destroyed synaptic function, as evidenced by impaired hippocampal long-term potentiation (LTP), decreased spine density, low number of synapses, and decreased postsynaptic protein (PSD95), and promoted the generation of amyloid β (Aβ) through increased expression of BACE1 and PS1 in the hippocampus of young APP/PS1 mice. Conclusions Together, our results indicate that CysLT1R upregulation accelerates memory impairment in young APP/PS1 mice, which is associated with promoting synaptic dysfunction and amyloidogenesis in the hippocampus.
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Affiliation(s)
- Shun-Chang Fang
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Jun-Jie Wang
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Fang Chen
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Su-Su Tang
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Rong-Hao Mu
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Dan-Hua Yuan
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Jia-Jia Zhao
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Hao Hong
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
| | - Yan Long
- Department of Pharmacology, Key Laboratory of Neuropsychiatric Diseases, China Pharmaceutical University, Nanjing, China
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The Type 2 Diabetes Factor Methylglyoxal Mediates Axon Initial Segment Shortening and Alters Neuronal Function at the Cellular and Network Levels. eNeuro 2021; 8:ENEURO.0201-21.2021. [PMID: 34531281 PMCID: PMC8496204 DOI: 10.1523/eneuro.0201-21.2021] [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: 05/06/2021] [Revised: 08/23/2021] [Accepted: 09/07/2021] [Indexed: 02/02/2023] Open
Abstract
Recent evidence suggests that alteration of axon initial segment (AIS) geometry (i.e., length or location along the axon) contributes to CNS dysfunction in neurological diseases. For example, AIS length is shorter in the prefrontal cortex of type 2 diabetic mice with cognitive impairment. To determine the key type 2 diabetes-related factor that produces AIS shortening we modified levels of insulin, glucose, or the reactive glucose metabolite methylglyoxal in cultures of dissociated cortices from male and female mice and quantified AIS geometry using immunofluorescent imaging of the AIS proteins AnkyrinG and βIV spectrin. Neither insulin nor glucose modification altered AIS length. Exposure to 100 but not 1 or 10 μm methylglyoxal for 24 h resulted in accumulation of the methylglyoxal-derived advanced glycation end-product hydroimidazolone and produced reversible AIS shortening without cell death. Methylglyoxal-evoked AIS shortening occurred in both excitatory and putative inhibitory neuron populations and in the presence of tetrodotoxin (TTX). In single-cell recordings resting membrane potential was depolarized at 0.5-3 h and returned to normal at 24 h. In multielectrode array (MEA) recordings methylglyoxal produced an immediate ∼300% increase in spiking and bursting rates that returned to normal within 2 min, followed by a ∼20% reduction of network activity at 0.5-3 h and restoration of activity to baseline levels at 24 h. AIS length was unchanged at 0.5-3 h despite the presence of depolarization and network activity reduction. Nevertheless, these results suggest that methylglyoxal could be a key mediator of AIS shortening and disruptor of neuronal function during type 2 diabetes.
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18
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Fisher EMC, Bannerman DM. Mouse models of neurodegeneration: Know your question, know your mouse. Sci Transl Med 2020; 11:11/493/eaaq1818. [PMID: 31118292 DOI: 10.1126/scitranslmed.aaq1818] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 02/26/2018] [Accepted: 06/19/2018] [Indexed: 12/19/2022]
Abstract
Many mutant mouse strains have been developed as models to investigate neurodegenerative disease in humans. However, variability in results among studies using these mouse strains has led to questions about the value of these models. Here, we appraise various mouse models for dissecting neurodegenerative disease mechanisms and emphasize the importance of asking appropriate research questions. In therapeutic studies, we suggest that understanding variability among and within mouse models is crucial for preventing translational failures in human patients.
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Affiliation(s)
- Elizabeth M C Fisher
- Department of Neuromuscular Diseases, University College London, London WC1N 3BG, UK.
| | - David M Bannerman
- Department of Experimental Psychology, University of Oxford, Oxford OX1 3TA, UK.
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Jiang R, Wu XF, Wang B, Guan RX, Lv LM, Li AP, Lei L, Ma Y, Li N, Li QF, Ma QH, Zhao J, Li S. Reduction of NgR in perforant path decreases amyloid-β peptide production and ameliorates synaptic and cognitive deficits in APP/PS1 mice. Alzheimers Res Ther 2020; 12:47. [PMID: 32331528 PMCID: PMC7181577 DOI: 10.1186/s13195-020-00616-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 04/07/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Amyloid beta (Aβ) which is recognized as a main feature of Alzheimer's disease (AD) has been proposed to "spread" through anatomically and functionally connected brain regions. The entorhinal cortex and perforant path are the earliest affected brain regions in AD. The perforant path is the most vulnerable circuit in the cortex with respect to both aging and AD. Previous data show that the origins and terminations of the perforant path are susceptible to amyloid deposition at the younger age in AD. Nogo receptor (NgR) plays an essential role in limiting injury-induced axonal growth and experience-dependent plasticity in the adult brain. It has been suggested that NgR is involved in AD pathological features, but the results have been conflicting and the detailed mechanism needs further investigation. In this study, the effect of NgR in the perforant path on the pathological and functional phenotype of APP/PS1 transgenic mice was studied. METHODS To genetically manipulate NgR expression, adeno-associated virus (AAV) with short hairpin (shRNA) against NgR was injected into the perforant path of APP/PS1 transgenic mice, followed by an assessment of behavioral, synaptic plasticity and neuropathological phenotypes. NgR was overexpressed or knockdown in neuroblastoma N2a cells and APPswe/HEK293 cells to investigate the interaction between NgR and amyloid precursor protein (APP). RESULTS It is shown that reduction of NgR in the perforant path rescued cognitive and synaptic deficits in APP/PS1 transgenic mice. Concurrently, Aβ production in the perforant path and levels of soluble Aβ and amyloid plaques in the hippocampus were significantly decreased. There was a positive correlation between the total APP protein level and NgR expression both in transgenic mice and in cultured cells, where the α-secretase and β-secretase cleavage products both changed with APP level in parallel. Finally, NgR might inhibit APP degradation through lysosome by Rho/Rho-associated protein kinases (ROCK) signaling pathway. CONCLUSIONS Our findings demonstrate that perforant path NgR plays an important role in regulating APP/Aβ level and cognitive functions in AD transgenic mice, which might be related to the suppression of APP degradation by NgR. Our study suggests that NgR in the perforant path could be a potential target for modulating AD progression.
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Affiliation(s)
- Rong Jiang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Xue-Fei Wu
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Bin Wang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Rong-Xiao Guan
- National-Local Joint Engineering Research Center for Drug Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, China
| | - Lang-Man Lv
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Ai-Ping Li
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Lei Lei
- National-Local Joint Engineering Research Center for Drug Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, China
| | - Ye Ma
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Na Li
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Qi-Fa Li
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
| | - Quan-Hong Ma
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Jie Zhao
- National-Local Joint Engineering Research Center for Drug Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, China
| | - Shao Li
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
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Yang F, Diao X, Wang F, Wang Q, Sun J, Zhou Y, Xie J. Identification of Key Regulatory Genes and Pathways in Prefrontal Cortex of Alzheimer's Disease. Interdiscip Sci 2020; 12:90-98. [PMID: 32006383 DOI: 10.1007/s12539-019-00353-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/28/2019] [Accepted: 11/30/2019] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder partly induced by dysregulation of different brain regions. Prefrontal cortex (PFC) dysregulation has been reported to associate with mental symptoms such as delusion, apathy, and depression in AD patients. However, the internal mechanisms have not yet been well-understood. This study aims to identify the potential therapeutic target genes and related pathways in PFC of AD. First, differential expression analyses were performed on transcriptome microarray of PFC between AD specimens and non-AD controls. Second, protein-protein interaction networks were constructed based on the identified differentially expressed genes to explore candidate therapeutic target genes. Finally, these candidate genes were validated through biological experiments. The enrichment analyses showed that the differentially expressed genes were significantly enriched in protein functions and pathways related to AD. Furthermore, the top ten hub genes in the protein-protein interaction network (ELAVL1, CUL3, MAPK6, FBXW11, YWHAE, YWHAZ, GRB2, CLTC, YWHAQ, and PDHA1) were proved to be directly or indirectly related to AD. Besides, six genes (PDHA1, CLTC, YWHAE, MAPK6, YWHAZ, and GRB2) of which were validated to significantly altered in AD mice by biological experiments. Importantly, the most significantly changed gene, PDHA1, was proposed for the first time that may be serve as a target gene in AD treatment. In summary, several genes and pathways that play critical roles in PFC of AD patients have been uncovered, which will provide novel insights on molecular targets for treatment and diagnostic biomarkers of AD.
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Affiliation(s)
- Fuzhang Yang
- School of Computer Engineering and Science, Shanghai University, Shanghai, China
| | - Xin Diao
- School of Computer Engineering and Science, Shanghai University, Shanghai, China
| | - Fushuai Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Quanwei Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Jiamin Sun
- School of Computer Engineering and Science, Shanghai University, Shanghai, China
| | - Yan Zhou
- Laboratory on Naturopathy, College of Physical Education, Shanghai University, Shanghai, China
| | - Jiang Xie
- School of Computer Engineering and Science, Shanghai University, Shanghai, China.
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Faldini E, Ahmed T, Bueé L, Blum D, Balschun D. Tau- but not Aß -pathology enhances NMDAR-dependent depotentiation in AD-mouse models. Acta Neuropathol Commun 2019; 7:202. [PMID: 31815648 PMCID: PMC6902514 DOI: 10.1186/s40478-019-0813-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/22/2019] [Indexed: 11/10/2022] Open
Abstract
Many mouse models of Alzheimer's disease (AD) exhibit impairments in hippocampal long-term-potentiation (LTP), seemingly corroborating the strong correlation between synaptic loss and cognitive decline reported in human studies. In other AD mouse models LTP is unaffected, but other defects in synaptic plasticity may still be present. We recently reported that THY-Tau22 transgenic mice, that overexpress human Tau protein carrying P301S and G272 V mutations and show normal LTP upon high-frequency-stimulation (HFS), develop severe changes in NMDAR mediated long-term-depression (LTD), the physiological counterpart of LTP. In the present study, we focused on putative effects of AD-related pathologies on depotentiation (DP), another form of synaptic plasticity. Using a novel protocol to induce DP in the CA1-region, we found in 11-15 months old male THY-Tau22 and APPPS1-21 transgenic mice that DP was not deteriorated by Aß pathology while significantly compromised by Tau pathology. Our findings advocate DP as a complementary form of synaptic plasticity that may help in elucidating synaptic pathomechanisms associated with different types of dementia.
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Ben-Nejma IRH, Keliris AJ, Daans J, Ponsaerts P, Verhoye M, Van der Linden A, Keliris GA. Increased soluble amyloid-beta causes early aberrant brain network hypersynchronisation in a mature-onset mouse model of amyloidosis. Acta Neuropathol Commun 2019; 7:180. [PMID: 31727182 PMCID: PMC6857138 DOI: 10.1186/s40478-019-0810-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 09/14/2019] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly. According to the amyloid hypothesis, the accumulation and deposition of amyloid-beta (Aβ) peptides play a key role in AD. Soluble Aβ (sAβ) oligomers were shown to be involved in pathological hypersynchronisation of brain resting-state networks in different transgenic developmental-onset mouse models of amyloidosis. However, the impact of protein overexpression during brain postnatal development may cause additional phenotypes unrelated to AD. To address this concern, we investigated sAβ effects on functional resting-state networks in transgenic mature-onset amyloidosis Tet-Off APP (TG) mice. TG mice and control littermates were raised on doxycycline (DOX) diet from 3d up to 3 m of age to suppress transgenic Aβ production. Thereafter, longitudinal resting-state functional MRI was performed on a 9.4 T MR-system starting from week 0 (3 m old mice) up to 28w post DOX treatment. Ex-vivo immunohistochemistry and ELISA analysis was performed to assess the development of amyloid pathology. Functional Connectivity (FC) analysis demonstrated early abnormal hypersynchronisation in the TG mice compared to the controls at 8w post DOX treatment, particularly across regions of the default mode-like network, known to be affected in AD. Ex-vivo analyses performed at this time point confirmed a 20-fold increase in total sAβ levels preceding the apparition of Aβ plaques and inflammatory responses in the TG mice compared to the controls. On the contrary at week 28, TG mice showed an overall hypoconnectivity, coinciding with a widespread deposition of Aβ plaques in the brain. By preventing developmental influence of APP and/or sAβ during brain postnatal development, we demonstrated FC abnormalities potentially driven by sAβ neurotoxicity on resting-state neuronal networks in mature-induced TG mice. Thus, the Tet-Off APP mouse model could be a powerful tool while used as a mature-onset model to shed light into amyloidosis mechanisms in AD.
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