1
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Jenkins PM, Bender KJ. Axon initial segment structure and function in health and disease. Physiol Rev 2025; 105:765-801. [PMID: 39480263 DOI: 10.1152/physrev.00030.2024] [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: 08/01/2024] [Revised: 10/18/2024] [Accepted: 10/23/2024] [Indexed: 11/06/2024] Open
Abstract
At the simplest level, neurons are structured to integrate synaptic input and perform computational transforms on that input, converting it into an action potential (AP) code. This process, converting synaptic input into AP output, typically occurs in a specialized region of the axon termed the axon initial segment (AIS). The AIS, as its name implies, is often contained to the first section of axon abutted to the soma and is home to a dizzying array of ion channels, attendant scaffolding proteins, intracellular organelles, extracellular proteins, and, in some cases, synapses. The AIS serves multiple roles as the final arbiter for determining if inputs are sufficient to evoke APs, as a gatekeeper that physically separates the somatodendritic domain from the axon proper, and as a regulator of overall neuronal excitability, dynamically tuning its size to best suit the needs of parent neurons. These complex roles have received considerable attention from experimentalists and theoreticians alike. Here, we review recent advances in our understanding of the AIS and its role in neuronal integration and polarity in health and disease.
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Affiliation(s)
- Paul M Jenkins
- Departments of Pharmacology and Psychiatry, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Kevin J Bender
- Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, California, United States
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2
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Burns AP, Fortel I, Zhan L, Lazarov O, Mackin RS, Demos AP, Bendlin B, Leow A. Longitudinal excitation-inhibition balance altered by sex and APOE-ε4. Commun Biol 2025; 8:488. [PMID: 40133608 PMCID: PMC11937384 DOI: 10.1038/s42003-025-07876-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2024] [Accepted: 03/03/2025] [Indexed: 03/27/2025] Open
Abstract
Neuronal hyperexcitation affects memory and neural processing across the Alzheimer's disease (AD) cognitive continuum. Levetiracetam, an antiepileptic, shows promise in improving cognitive impairment by restoring the neural excitation/inhibition balance in AD patients. We previously identified a hyper-excitable phenotype in cognitively unimpaired female APOE-ε4 carriers relative to male counterparts cross-sectionally. This sex difference lacks longitudinal validation; however, clarifying the vulnerability of female ε4-carriers could better inform antiepileptic treatment efficacy. Here, we investigated this sex-by-ε4 interaction using a longitudinal design. We used resting-state fMRI and diffusion tensor imaging collected longitudinally from 106 participants who were cognitively unimpaired for at least one scan event but may have been assessed to have clinical dementia ratings corresponding to early mild cognitive impairment over time. By including scan events where participants transitioned to mild cognitive impairment, we modeled the trajectory of the whole-brain excitation-inhibition ratio throughout the preclinical cognitively healthy continuum and extended to early impairment. A linear mixed model revealed a significant three-way interaction among sex, ε4-status, and time, with female ε4-carriers showing a significant hyper-excitable trajectory. These findings suggest a possible pathway for preventative therapy targeting preclinical hyperexcitation in female ε4-carriers.
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Affiliation(s)
- Andrew P Burns
- Department of Biomedical Engineering University of Illinois Chicago (UIC), 851 S Morgan St, Chicago, IL, 60607, USA.
| | - Igor Fortel
- Department of Biomedical Engineering University of Illinois Chicago (UIC), 851 S Morgan St, Chicago, IL, 60607, USA
| | - Liang Zhan
- Department of Electrical and Computer Engineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA, 15260, USA
| | - Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, 808 S. Wood St, Chicago, IL, 60612, USA
| | - R Scott Mackin
- Department of Psychiatry and Behavioral Sciences, University of California San Francisco, 675 18th St, San Francisco, CA, 94107, USA
- Department of Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA, USA
| | - Alexander P Demos
- Department of Psychology, University of Illinois Chicago (UIC), 1007 W Harrison St, Chicago, IL, 60607, USA
| | - Barbara Bendlin
- Department of Medicine, University of Wisconsin-Madison, 5158 Medical Foundation Centennial Building, 1685 Highland Ave, Madison, WI, 53792, USA
- Wisconsin Alzheimer's Disease Research Center, University of Wisconsin-Madison, 600 Highland Ave J5/1 Mezzanine, Madison, WI, 53792, USA
| | - Alex Leow
- Department of Biomedical Engineering University of Illinois Chicago (UIC), 851 S Morgan St, Chicago, IL, 60607, USA.
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3
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Fréal A, Hoogenraad CC. The dynamic axon initial segment: From neuronal polarity to network homeostasis. Neuron 2025; 113:649-669. [PMID: 39947181 DOI: 10.1016/j.neuron.2025.01.004] [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: 09/15/2024] [Accepted: 01/07/2025] [Indexed: 03/08/2025]
Abstract
The axon initial segment (AIS) is a highly specialized compartment in neurons that resides in between axonal and somatodendritic domains. The localization of the AIS in the proximal part of the axon is essential for its two major functions: generating and modulating action potentials and maintaining neuron polarity. Recent findings revealed that the incredibly stable AIS is generated from highly dynamic components and can undergo extensive structural and functional changes in response to alterations in activity levels. These activity-dependent alterations of AIS structure and function have profound consequences for neuronal functioning, and AIS plasticity has emerged as a key regulator of network homeostasis. This review highlights the functions of the AIS, its architecture, and how its organization and remodeling are influenced by developmental plasticity and both acute and chronic adaptations. It also discusses the mechanisms underlying these processes and explores how dysregulated AIS plasticity may contribute to brain disorders.
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Affiliation(s)
- Amélie Fréal
- Amsterdam UMC location Vrije Universiteit Amsterdam, Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Amsterdam, the Netherlands
| | - Casper C Hoogenraad
- Department of Neuroscience, Genentech, Inc, South San Francisco, CA 94080, USA.
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4
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Jiang S, Hijazi S, Sarkany B, Gautsch VG, LaChance PA, Hasselmo ME, Bannerman D, Viney TJ. Pathological tau alters head direction signaling and induces spatial disorientation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.11.07.622548. [PMID: 39574637 PMCID: PMC11581017 DOI: 10.1101/2024.11.07.622548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2024]
Abstract
Spatial disorientation, an early symptom of dementia, is emerging as an early and reliable cognitive biomarker predicting future memory problems associated with Alzheimer's disease, but the underlying neural mechanisms have yet to be fully defined. The anterodorsal thalamic nucleus (ADn) exhibits early and selective vulnerability to pathological misfolded forms of tau, a major hallmark of Alzheimer's disease and ageing. The ADn contains a high density of head direction (HD) cells, which contribute to spatial navigation and orientation. Hence, their disruption may contribute to spatial disorientation. To test this, we virally expressed human mutant tau (htau) in the ADn of adult mice. HD-tau mice were defined by phosphorylated and oligomeric forms of htau in ADn somata and in axon terminals in postsynaptic target regions. Compared to controls, HD-tau mice exhibited increased looping behavior during spatial learning, and made a greater number of head turns during memory recall, indicative of spatial disorientation. Using in vivo extracellular recordings, we identified htau-expressing ADn cells and found a lower proportion of HD cells in the ADn from HD-tau mice, along with reduced directionality and altered burst firing. These findings provide evidence that expression of pathological human tau can alter HD signaling, leading to impairments in spatial orientation.
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5
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Gong B, Zhang W, Cong W, Gu Y, Ji W, Yin T, Zhou H, Hu H, Zhuang J, Luo Y, Liu Y, Gao J, Yin Y. Systemic Administration of Neurotransmitter-Derived Lipidoids-PROTACs-DNA Nanocomplex Promotes Tau Clearance and Cognitive Recovery for Alzheimer's Disease Therapy. Adv Healthc Mater 2024; 13:e2400149. [PMID: 39007278 DOI: 10.1002/adhm.202400149] [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: 02/01/2024] [Revised: 06/10/2024] [Indexed: 07/16/2024]
Abstract
Alzheimer's disease (AD) poses a significant burden on the economy and healthcare systems worldwide. Although the pathophysiology of AD remains debatable, its progression is strongly correlated with the accumulation of tau aggregates. Therefore, tau clearance from brain lesions can be a promising strategy for AD therapy. To achieve this, the present study combined proteolysis-targeting chimera (PROTAC), a novel protein-degradation technique that mediates degradation of target proteins via the ubiquitin-proteasome system, and a neurotransmitter-derived lipidoid (NT-lipidoid) nanoparticle delivery system with high blood-brain barrier-penetration activity, to generate a novel nanomedicine named NPD. Peptide 1, a cationic tau-targeting PROTAC is loaded onto the positively charged nanoparticles using DNA-intercalation technology. The resulting nanomedicine displayed good encapsulation efficiency, serum stability, drug release profile, and blood-brain barrier-penetration capability. Furthermore, NPD potently induced tau clearance in both cultured neuronal cells and the brains of AD mice. Moreover, intravenous injection of NPD led to a significant improvement in the cognitive function of the AD mice, without any remarkable abnormalities, thereby supporting its clinical development. Collectively, the novel nanomedicine developed in this study may serve as an innovative strategy for AD therapy, since it effectively and specifically induces tau protein clearance in brain lesions, which in turn enhances cognition.
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Affiliation(s)
- Baofeng Gong
- Department of Neurology, Second Affiliated Hospital (Shanghai Changzheng Hospital) of Naval Medical University, Shanghai, 200003, China
| | - Weicong Zhang
- School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Wei Cong
- School of Medicine, Shanghai University, Shanghai, 200444, China
| | - Yuankai Gu
- Department of Neurology, Second Affiliated Hospital (Shanghai Changzheng Hospital) of Naval Medical University, Shanghai, 200003, China
| | - Wenbo Ji
- Department of Neurology, Second Affiliated Hospital (Shanghai Changzheng Hospital) of Naval Medical University, Shanghai, 200003, China
| | - Tong Yin
- Department of Neurology, Second Affiliated Hospital (Shanghai Changzheng Hospital) of Naval Medical University, Shanghai, 200003, China
| | - Honglei Zhou
- Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Honggang Hu
- School of Medicine, Shanghai University, Shanghai, 200444, China
| | - Jianhua Zhuang
- Department of Neurology, Second Affiliated Hospital (Shanghai Changzheng Hospital) of Naval Medical University, Shanghai, 200003, China
| | - Yi Luo
- New Drug Discovery and Development, Biotheus Inc., Zhuhai, 519080, China
- Clinical Pharmacy Innovation Institute, Shanghai Jiao Tong University of Medicine, Shanghai, 200240, China
| | - Yan Liu
- Clinical Pharmacy Innovation Institute, Shanghai Jiao Tong University of Medicine, Shanghai, 200240, China
- Department of Clinical Pharmacy, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China
| | - Jie Gao
- Changhai Clinical Research Unit, Shanghai Changhai Hospital, Naval Medical University, Shanghai, 200433, China
| | - You Yin
- Department of Neurology, Second Affiliated Hospital (Shanghai Changzheng Hospital) of Naval Medical University, Shanghai, 200003, China
- Department of Neurology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
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van Nifterick AM, de Haan W, Stam CJ, Hillebrand A, Scheltens P, van Kesteren RE, Gouw AA. Functional network disruption in cognitively unimpaired autosomal dominant Alzheimer's disease: a magnetoencephalography study. Brain Commun 2024; 6:fcae423. [PMID: 39713236 PMCID: PMC11660908 DOI: 10.1093/braincomms/fcae423] [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: 07/15/2024] [Revised: 10/09/2024] [Accepted: 11/22/2024] [Indexed: 12/24/2024] Open
Abstract
Understanding the nature and onset of neurophysiological changes, and the selective vulnerability of central hub regions in the functional network, may aid in managing the growing impact of Alzheimer's disease on society. However, the precise neurophysiological alterations occurring in the pre-clinical stage of human Alzheimer's disease remain controversial. This study aims to provide increased insights on quantitative neurophysiological alterations during a true early stage of Alzheimer's disease. Using high spatial resolution source-reconstructed magnetoencephalography, we investigated regional and whole-brain neurophysiological changes in a unique cohort of 11 cognitively unimpaired individuals with pathogenic mutations in the presenilin-1 or amyloid precursor protein gene and a 1:3 matched control group (n = 33) with a median age of 49 years. We examined several quantitative magnetoencephalography measures that have been shown robust in detecting differences in sporadic Alzheimer's disease patients and are sensitive to excitation-inhibition imbalance. This includes spectral power and functional connectivity in different frequency bands. We also investigated hub vulnerability using the hub disruption index. To understand how magnetoencephalography measures change as the disease progresses through its pre-clinical stage, correlations between magnetoencephalography outcomes and various clinical variables like age were analysed. A comparison of spectral power between mutation carriers and controls revealed oscillatory slowing, characterized by widespread higher theta (4-8 Hz) power, a lower posterior peak frequency and lower occipital alpha 2 (10-13 Hz) power. Functional connectivity analyses presented a lower whole-brain (amplitude-based) functional connectivity in the alpha (8-13 Hz) and beta (13-30 Hz) bands, predominantly located in parieto-temporal hub regions. Furthermore, we found a significant hub disruption index for (phase-based) functional connectivity in the theta band, attributed to both higher functional connectivity in 'non-hub' regions alongside a hub disruption. Neurophysiological changes did not correlate with indicators of pre-clinical disease progression in mutation carriers after multiple comparisons correction. Our findings provide evidence that oscillatory slowing and functional connectivity differences occur before cognitive impairment in individuals with autosomal dominant mutations leading to early onset Alzheimer's disease. The nature and direction of these alterations are comparable to those observed in the clinical stages of Alzheimer's disease, suggest an early excitation-inhibition imbalance, and fit with the activity-dependent functional degeneration hypothesis. These insights may prove useful for early diagnosis and intervention in the future.
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Affiliation(s)
- Anne M van Nifterick
- Alzheimer Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, 1081 HZ Amsterdam, The Netherlands
- Clinical Neurophysiology and MEG Center, Neurology, Amsterdam UMC Location VUmc, 1081 HV Amsterdam, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, 1081 HV Amsterdam, The Netherlands
| | - Willem de Haan
- Alzheimer Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, 1081 HZ Amsterdam, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, 1081 HV Amsterdam, The Netherlands
| | - Cornelis J Stam
- Clinical Neurophysiology and MEG Center, Neurology, Amsterdam UMC Location VUmc, 1081 HV Amsterdam, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, 1081 HV Amsterdam, The Netherlands
| | - Arjan Hillebrand
- Clinical Neurophysiology and MEG Center, Neurology, Amsterdam UMC Location VUmc, 1081 HV Amsterdam, The Netherlands
- Amsterdam Neuroscience, Brain Imaging, 1081 HV Amsterdam, The Netherlands
- Amsterdam Neuroscience, Systems and Network Neurosciences, 1081 HV Amsterdam, The Netherlands
| | - Philip Scheltens
- Alzheimer Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, 1081 HZ Amsterdam, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, 1081 HV Amsterdam, The Netherlands
| | - Ronald E van Kesteren
- Amsterdam Neuroscience, Neurodegeneration, 1081 HV Amsterdam, The Netherlands
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Alida A Gouw
- Alzheimer Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, 1081 HZ Amsterdam, The Netherlands
- Clinical Neurophysiology and MEG Center, Neurology, Amsterdam UMC Location VUmc, 1081 HV Amsterdam, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, 1081 HV Amsterdam, The Netherlands
- Amsterdam Neuroscience, Systems and Network Neurosciences, 1081 HV Amsterdam, The Netherlands
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7
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McGregor JN, Farris CA, Ensley S, Schneider A, Fosque LJ, Wang C, Tilden EI, Liu Y, Tu J, Elmore H, Ronayne KD, Wessel R, Dyer EL, Bhaskaran-Nair K, Holtzman DM, Hengen KB. Failure in a population: Tauopathy disrupts homeostatic set-points in emergent dynamics despite stability in the constituent neurons. Neuron 2024; 112:3567-3584.e5. [PMID: 39241778 PMCID: PMC11560743 DOI: 10.1016/j.neuron.2024.08.006] [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: 09/06/2023] [Revised: 06/24/2024] [Accepted: 08/09/2024] [Indexed: 09/09/2024]
Abstract
Homeostatic regulation of neuronal activity is essential for robust computation; set-points, such as firing rate, are actively stabilized to compensate for perturbations. The disruption of brain function central to neurodegenerative disease likely arises from impairments of computationally essential set-points. Here, we systematically investigated the effects of tau-mediated neurodegeneration on all known set-points in neuronal activity. We continuously tracked hippocampal neuronal activity across the lifetime of a mouse model of tauopathy. We were unable to detect effects of disease in measures of single-neuron firing activity. By contrast, as tauopathy progressed, there was disruption of network-level neuronal activity, quantified by measuring neuronal pairwise interactions and criticality, a homeostatically controlled, ideal computational regime. Deviations in criticality correlated with symptoms, predicted underlying anatomical pathology, occurred in a sleep-wake-dependent manner, and could be used to reliably classify an animal's genotype. This work illustrates how neurodegeneration may disrupt the computational capacity of neurobiological systems.
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Affiliation(s)
- James N McGregor
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Clayton A Farris
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Sahara Ensley
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Aidan Schneider
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Leandro J Fosque
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Chao Wang
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University in Saint Louis, St. Louis, MO, USA; Institute for Brain Science and Disease, Chongqing Medical University, Chongqing 400016, China
| | - Elizabeth I Tilden
- Department of Neuroscience, Washington University in Saint Louis, St. Louis, MO, USA
| | - Yuqi Liu
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Jianhong Tu
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Halla Elmore
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Keenan D Ronayne
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Ralf Wessel
- Department of Physics, Washington University in Saint Louis, St. Louis, MO, USA
| | - Eva L Dyer
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University in Saint Louis, St. Louis, MO, USA
| | - Keith B Hengen
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA.
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8
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Sharma P, Sharma S, Yadav Y, Shukla P, Sagar R. Current pharmacophore based approaches for the development of new anti-Alzheimer's agents. Bioorg Med Chem 2024; 113:117926. [PMID: 39306973 DOI: 10.1016/j.bmc.2024.117926] [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: 07/24/2024] [Revised: 09/06/2024] [Accepted: 09/10/2024] [Indexed: 10/13/2024]
Abstract
Amyloid beta peptide (Aβ) and hyperphosphorylated neuronal tau proteins accumulate in neurofibrillary tangles in Alzheimer's disease (AD), a chronic neurodegenerative illness. Chronic inflammation in the brain, which promotes disease progression, is another feature of the Alzheimer's disease pathogenesis. Approximately 60-70 % of dementia cases are caused by AD. The development of effective therapies for the treatment of AD is urgently needed given the severity of the condition and its rapidly rising prevalence. Cholinesterase inhibitors, beta-amyloid (A-beta), tau inhibitors, and many other medications are currently used as preventive medicine for AD. These medications can temporarily suppress dementia symptoms but cannot halt or reverse the disease's progression. Many international pharmaceutical companies have tried numerous times to develop an amyloid clearing medication based on the amyloid hypothesis, but without success. Therefore, the amyloid theory may not be entirely plausible. This review mainly covers the recent and important reported pharmacophores as the starting point to discuss already known targets like tau, butyrylcholinesterase, amyloid beta, and acetylcholinesterase and covers the literature between years 2019-2024.
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Affiliation(s)
- Prachi Sharma
- Department of Chemistry, Birla Institute of Technology and Sciences, Pilani, Rajasthan 333031, India
| | - Sunil Sharma
- Glycochemistry Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Yogesh Yadav
- Glycochemistry Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Paritosh Shukla
- Department of Chemistry, Birla Institute of Technology and Sciences, Pilani, Rajasthan 333031, India.
| | - Ram Sagar
- Glycochemistry Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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9
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Qi Y, Zhao R, Tian J, Lu J, He M, Tai Y. Specific and Plastic: Chandelier Cell-to-Axon Initial Segment Connections in Shaping Functional Cortical Network. Neurosci Bull 2024; 40:1774-1788. [PMID: 39080101 PMCID: PMC11607270 DOI: 10.1007/s12264-024-01266-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 03/19/2024] [Indexed: 11/30/2024] Open
Abstract
Axon initial segment (AIS) is the most excitable subcellular domain of a neuron for action potential initiation. AISs of cortical projection neurons (PNs) receive GABAergic synaptic inputs primarily from chandelier cells (ChCs), which are believed to regulate action potential generation and modulate neuronal excitability. As individual ChCs often innervate hundreds of PNs, they may alter the activity of PN ensembles and even impact the entire neural network. During postnatal development or in response to changes in network activity, the AISs and axo-axonic synapses undergo dynamic structural and functional changes that underlie the wiring, refinement, and adaptation of cortical microcircuits. Here we briefly introduce the history of ChCs and review recent research advances employing modern genetic and molecular tools. Special attention will be attributed to the plasticity of the AIS and the ChC-PN connections, which play a pivotal role in shaping the dynamic network under both physiological and pathological conditions.
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Affiliation(s)
- Yanqing Qi
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Rui Zhao
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Jifeng Tian
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Jiangteng Lu
- Songjiang Research Institute, Shanghai Songjiang District Central Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200025, China
- Center for Brain Science of Shanghai Children's Medical Center, Department of Anatomy and Physiology, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Miao He
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Yilin Tai
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurobiology, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
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10
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Li J, Liu Y, Yin C, Zeng Y, Mei Y. Structural and functional remodeling of neural networks in β-amyloid driven hippocampal hyperactivity. Ageing Res Rev 2024; 101:102468. [PMID: 39218080 DOI: 10.1016/j.arr.2024.102468] [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: 06/01/2024] [Revised: 08/19/2024] [Accepted: 08/21/2024] [Indexed: 09/04/2024]
Abstract
Early detection of Alzheimer's disease (AD) is essential for improving the patients outcomes and advancing our understanding of disease, allowing for timely intervention and treatment. However, accurate biomarkers are still lacking. Recent evidence indicates that hippocampal hyperexcitability precedes the diagnosis of AD decades ago, can predict cognitive decline. Thus, could hippocampal hyperactivity be a robust biomarker for early-AD, and what drives hippocampal hyperactivity in early-AD? these critical questions remain to be answered. Increasing clinical and experimental studies suggest that early hippocampal activation is closely associated with longitudinal β-amyloid (Aβ) accumulation, Aβ aggregates, in turn, enhances hippocampal activity. Therefore, in this narrative review, we discuss the role of Aβ-induced altered intrinsic neuronal properties as well as structural and functional remodeling of glutamatergic, GABAergic, cholinergic, noradrenergic, serotonergic circuits in hippocampal hyperactivity. In addition, we analyze the available therapies and trials that can potentially be used clinically to attenuate hippocampal hyperexcitability in AD. Overall, the present review sheds lights on the mechanism behind Aβ-induced hippocampal hyperactivity, and highlights that hippocampal hyperactivity could be a robust biomarker and therapeutic target in prodromal AD.
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Affiliation(s)
- Jinquan Li
- Hubei Clinical Research Center for Alzheimer's Disease, Brain Science and Advanced Technology Institute, School of Medicine, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Yanjun Liu
- Hubei Clinical Research Center for Alzheimer's Disease, Brain Science and Advanced Technology Institute, School of Medicine, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Chuhui Yin
- Hubei Clinical Research Center for Alzheimer's Disease, Brain Science and Advanced Technology Institute, School of Medicine, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Yan Zeng
- Hubei Clinical Research Center for Alzheimer's Disease, Brain Science and Advanced Technology Institute, School of Medicine, Wuhan University of Science and Technology, Wuhan 430065, China.
| | - Yufei Mei
- Hubei Clinical Research Center for Alzheimer's Disease, Brain Science and Advanced Technology Institute, School of Medicine, Wuhan University of Science and Technology, Wuhan 430065, China.
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11
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Benitez MJ, Retana D, Ordoñez-Gutiérrez L, Colmena I, Goméz MJ, Álvarez R, Ciorraga M, Dopazo A, Wandosell F, Garrido JJ. Transcriptomic alterations in APP/PS1 mice astrocytes lead to early postnatal axon initial segment structural changes. Cell Mol Life Sci 2024; 81:444. [PMID: 39485512 PMCID: PMC11530419 DOI: 10.1007/s00018-024-05485-9] [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: 10/10/2023] [Revised: 09/20/2024] [Accepted: 10/21/2024] [Indexed: 11/03/2024]
Abstract
Alzheimer´s disease (AD) is characterized by neuronal function loss and degeneration. The integrity of the axon initial segment (AIS) is essential to maintain neuronal function and output. AIS alterations are detected in human post-mortem AD brains and mice models, as well as, neurodevelopmental and mental disorders. However, the mechanisms leading to AIS deregulation in AD and the extrinsic glial origin are elusive. We studied early postnatal differences in AIS cellular/molecular mechanisms in wild-type or APP/PS1 mice and combined neuron-astrocyte co-cultures. We observed AIS integrity alterations, reduced ankyrinG expression and shortening, in APP/PS1 mice from P21 and loss of AIS integrity at 21 DIV in wild-type and APP/PS1 neurons in the presence of APP/PS1 astrocytes. AnkyrinG decrease is due to mRNAs and protein reduction of retinoic acid synthesis enzymes Rdh1 and Aldh1b1, as well as ADNP (Activity-dependent neuroprotective protein) in APP/PS1 astrocytes. This effect was mimicked by wild-type astrocytes expressing ADNP shRNA. In the presence of APP/PS1 astrocytes, wild-type neurons AIS is recovered by inhibition of retinoic acid degradation, and Adnp-derived NAP peptide (NAPVSIPQ) addition or P2X7 receptor inhibition, both regulated by retinoic acid levels. Moreover, P2X7 inhibitor treatment for 2 months impaired AIS disruption in APP/PS1 mice. Our findings extend current knowledge on AIS regulation, providing data to support the role of astrocytes in early postnatal AIS modulation. In conclusion, AD onset may be related to very early glial cell alterations that induce AIS and neuronal function changes, opening new therapeutic approaches to detect and avoid neuronal function loss.
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Affiliation(s)
- María José Benitez
- Instituto Cajal, CSIC, Madrid, Spain
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Lara Ordoñez-Gutiérrez
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBER-ISCIII), Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Inés Colmena
- Instituto Cajal, CSIC, Madrid, Spain
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBER-ISCIII), Madrid, Spain
| | | | - Rebeca Álvarez
- Genomics Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | | | - Ana Dopazo
- Genomics Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Francisco Wandosell
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBER-ISCIII), Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan José Garrido
- Instituto Cajal, CSIC, Madrid, Spain.
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBER-ISCIII), Madrid, Spain.
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12
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Parra Bravo C, Naguib SA, Gan L. Cellular and pathological functions of tau. Nat Rev Mol Cell Biol 2024; 25:845-864. [PMID: 39014245 DOI: 10.1038/s41580-024-00753-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2024] [Indexed: 07/18/2024]
Abstract
Tau protein is involved in various cellular processes, including having a canonical role in binding and stabilization of microtubules in neurons. Tauopathies are neurodegenerative diseases marked by the abnormal accumulation of tau protein aggregates in neurons, as seen, for example, in conditions such as frontotemporal dementia and Alzheimer disease. Mutations in tau coding regions or that disrupt tau mRNA splicing, tau post-translational modifications and cellular stress factors (such as oxidative stress and inflammation) increase the tendency of tau to aggregate and interfere with its clearance. Pathological tau is strongly implicated in the progression of neurodegenerative diseases, and the propagation of tau aggregates is associated with disease severity. Recent technological advancements, including cryo-electron microscopy and disease models derived from human induced pluripotent stem cells, have increased our understanding of tau-related pathology in neurodegenerative conditions. Substantial progress has been made in deciphering tau aggregate structures and the molecular mechanisms that underlie protein aggregation and toxicity. In this Review, we discuss recent insights into the diverse cellular functions of tau and the pathology of tau inclusions and explore the potential for therapeutic interventions.
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Affiliation(s)
- Celeste Parra Bravo
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Neuroscience Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Sarah A Naguib
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Li Gan
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
- Neuroscience Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA.
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13
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Cortés Malagón EM, López Ornelas A, Olvera Gómez I, Bonilla Delgado J. The Kynurenine Pathway, Aryl Hydrocarbon Receptor, and Alzheimer's Disease. Brain Sci 2024; 14:950. [PMID: 39335444 PMCID: PMC11429728 DOI: 10.3390/brainsci14090950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2024] [Revised: 09/12/2024] [Accepted: 09/21/2024] [Indexed: 09/30/2024] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia, mainly affecting elderly individuals. AD is characterized by β-amyloid plaques, abnormal tau tangles, neuronal loss, and metabolic disruptions. Recent studies have revealed the involvement of the kynurenine (KP) pathway and the aryl hydrocarbon receptor (AhR) in AD development. The KP pathway metabolizes tryptophan to produce neuroactive substances like kynurenine, kynurenic acid, and quinolinic acid. In AD, high levels of kynurenine and the neurotoxic quinolinic acid are associated with increased neuroinflammation and excitotoxicity; conversely, reduced levels of kynurenic acid, which acts as a glutamate receptor antagonist, compromise neuroprotection. Research has indicated elevated KP metabolites and enzymes in the hippocampus of AD patients and other tissues such as blood, cerebrospinal fluid, and urine. However, the finding that KP metabolites are AD biomarkers in blood, cerebrospinal fluid, and urine has been controversial. This controversy, stemming from the lack of consideration of the specific stage of AD, details of the patient's treatment, cognitive deficits, and psychiatric comorbidities, underscores the need for more comprehensive research. AhR, a ligand-activated transcription factor, regulates immune response, oxidative stress, and xenobiotic metabolism. Various ligands, including tryptophan metabolites, can activate it. Some studies suggest that AhR activation contributes to AD, while others propose that it provides neuroprotection. This discrepancy may be explained by the specific ligands that activate AhR, highlighting the complex relationship between the KP pathway, AhR activation, and AD, where the same pathway can produce both neuroprotective and harmful effects.
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Affiliation(s)
- Enoc Mariano Cortés Malagón
- Research Division, Hospital Juárez de México, Mexico City 07760, Mexico; (E.M.C.M.); (A.L.O.); (I.O.G.)
- Genetics Laboratory, Hospital Nacional Homeopático, Mexico City 06800, Mexico
| | - Adolfo López Ornelas
- Research Division, Hospital Juárez de México, Mexico City 07760, Mexico; (E.M.C.M.); (A.L.O.); (I.O.G.)
- Genetics Laboratory, Hospital Nacional Homeopático, Mexico City 06800, Mexico
| | - Irlanda Olvera Gómez
- Research Division, Hospital Juárez de México, Mexico City 07760, Mexico; (E.M.C.M.); (A.L.O.); (I.O.G.)
- Facultad Ciencias de la Salud, Universidad Anáhuac Norte, Estado de México 52786, Mexico
| | - José Bonilla Delgado
- Research Unit, Hospital Regional de Alta Especialidad de Ixtapaluca, IMSS-BINESTAR, Ixtapaluca 56530, Mexico
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14
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Wodrich APK, Harris BT, Giniger E. Changes in mitochondrial distribution occur at the axon initial segment in association with neurodegeneration in Drosophila. Biol Open 2024; 13:bio060335. [PMID: 38912559 PMCID: PMC11261633 DOI: 10.1242/bio.060335] [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: 01/26/2024] [Accepted: 06/17/2024] [Indexed: 06/25/2024] Open
Abstract
Changes in mitochondrial distribution are a feature of numerous age-related neurodegenerative diseases. In Drosophila, reducing the activity of Cdk5 causes a neurodegenerative phenotype and is known to affect several mitochondrial properties. Therefore, we investigated whether alterations of mitochondrial distribution are involved in Cdk5-associated neurodegeneration. We find that reducing Cdk5 activity does not alter the balance of mitochondrial localization to the somatodendritic versus axonal neuronal compartments of the mushroom body, the learning and memory center of the Drosophila brain. We do, however, observe changes in mitochondrial distribution at the axon initial segment (AIS), a neuronal compartment located in the proximal axon involved in neuronal polarization and action potential initiation. Specifically, we observe that mitochondria are partially excluded from the AIS in wild-type neurons, but that this exclusion is lost upon reduction of Cdk5 activity, concomitant with the shrinkage of the AIS domain that is known to occur in this condition. This mitochondrial redistribution into the AIS is not likely due to the shortening of the AIS domain itself but rather due to altered Cdk5 activity. Furthermore, mitochondrial redistribution into the AIS is unlikely to be an early driver of neurodegeneration in the context of reduced Cdk5 activity.
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Affiliation(s)
- Andrew P. K. Wodrich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007, USA
- College of Medicine, University of Kentucky, Lexington, KY 40506, USA
| | - Brent T. Harris
- Department of Pathology, Georgetown University, Washington, DC 20007, USA
- Department of Neurology, Georgetown University, Washington, DC 20007, USA
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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15
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Micinski D, Hotulainen P. Actin polymerization and longitudinal actin fibers in axon initial segment plasticity. Front Mol Neurosci 2024; 17:1376997. [PMID: 38799616 PMCID: PMC11120970 DOI: 10.3389/fnmol.2024.1376997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/26/2024] [Indexed: 05/29/2024] Open
Abstract
The location of the axon initial segment (AIS) at the junction between the soma and axon of neurons makes it instrumental in maintaining neural polarity and as the site for action potential generation. The AIS is also capable of large-scale relocation in an activity-dependent manner. This represents a form of homeostatic plasticity in which neurons regulate their own excitability by changing the size and/or position of the AIS. While AIS plasticity is important for proper functionality of AIS-containing neurons, the cellular and molecular mechanisms of AIS plasticity are poorly understood. Here, we analyzed changes in the AIS actin cytoskeleton during AIS plasticity using 3D structured illumination microscopy (3D-SIM). We showed that the number of longitudinal actin fibers increased transiently 3 h after plasticity induction. We further showed that actin polymerization, especially formin mediated actin polymerization, is required for AIS plasticity and formation of longitudinal actin fibers. From the formin family of proteins, Daam1 localized to the ends of longitudinal actin fibers. These results indicate that active re-organization of the actin cytoskeleton is required for proper AIS plasticity.
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Affiliation(s)
- David Micinski
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- HiLIFE-Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Pirta Hotulainen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Faculty of Medicine, University of Helsinki, Helsinki, Finland
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16
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Su J, Xiao Y, Wei L, Lei H, Sun F, Wang W, Yin J, Xiong R, Li S, Zhang P, Zhou Y, Wang X, Zheng J, Wang JZ. Generation of tau dephosphorylation-targeting chimeras for the treatment of Alzheimer's disease and related tauopathies. Sci Bull (Beijing) 2024; 69:1137-1152. [PMID: 38341350 DOI: 10.1016/j.scib.2024.01.019] [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: 10/04/2023] [Revised: 12/06/2023] [Accepted: 01/08/2024] [Indexed: 02/12/2024]
Abstract
Abnormal hyperphosphorylation and accumulation of tau protein play a pivotal role in neurodegeneration in Alzheimer's disease (AD) and many other tauopathies. Selective elimination of hyperphosphorylated tau is promising for the therapy of these diseases. We have conceptualized a strategy, named dephosphorylation-targeting chimeras (DEPTACs), for specifically hijacking phosphatases to tau to debilitate its hyperphosphorylation. Here, we conducted the step-by-step optimization of each constituent motif to generate DEPTACs with reasonable effectiveness in facilitating the dephosphorylation and subsequent clearance of pathological tau. Specifically, for one of the selected chimeras, D16, we demonstrated its significant efficiency in rescuing the neurodegeneration caused by neurotoxic K18-tau seeds in vitro. Moreover, intravenous administration of D16 also alleviated tau pathologies in the brain and improved memory deficits in AD mice. These results suggested DEPTACs as targeted modulators of tau phosphorylation, which hold therapeutic potential for AD and other tauopathies.
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Affiliation(s)
- Jingfen Su
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yue Xiao
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; School of Artificial Intelligence and Automation, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Linyu Wei
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Sino-UK Joint Laboratory of Brain Function and Injury of Henan Province, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China
| | - Huiyang Lei
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Fei Sun
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Weixia Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jun Yin
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430030, China
| | - Rui Xiong
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shihong Li
- Department of Anesthesiology, The First Affiliated Hospital of Gannan Medical University, Ganzhou 341000, China
| | - Pei Zhang
- The Core Facility and Technical Support, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430030, China
| | - Ying Zhou
- Research Center for Medicine and Structural Biology, Wuhan University, Wuhan 430030, China
| | - Xiaochuan Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; School of Artificial Intelligence and Automation, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Jie Zheng
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Beijing 100083, China.
| | - Jian-Zhi Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226000, China.
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17
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Lei HY, Pi GL, He T, Xiong R, Lv JR, Liu JL, Wu DQ, Li MZ, Shi K, Li SH, Yu NN, Gao Y, Yu HL, Wei LY, Wang X, Zhou QZ, Zou PL, Zhou JY, Liu YZ, Shen NT, Yang J, Ke D, Wang Q, Liu GP, Yang XF, Wang JZ, Yang Y. Targeting vulnerable microcircuits in the ventral hippocampus of male transgenic mice to rescue Alzheimer-like social memory loss. Mil Med Res 2024; 11:16. [PMID: 38462603 PMCID: PMC10926584 DOI: 10.1186/s40779-024-00512-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 01/11/2024] [Indexed: 03/12/2024] Open
Abstract
BACKGROUND Episodic memory loss is a prominent clinical manifestation of Alzheimer's disease (AD), which is closely related to tau pathology and hippocampal impairment. Due to the heterogeneity of brain neurons, the specific roles of different brain neurons in terms of their sensitivity to tau accumulation and their contribution to AD-like social memory loss remain unclear. Therefore, further investigation is necessary. METHODS We investigated the effects of AD-like tau pathology by Tandem mass tag proteomic and phosphoproteomic analysis, social behavioural tests, hippocampal electrophysiology, immunofluorescence staining and in vivo optical fibre recording of GCaMP6f and iGABASnFR. Additionally, we utilized optogenetics and administered ursolic acid (UA) via oral gavage to examine the effects of these agents on social memory in mice. RESULTS The results of proteomic and phosphoproteomic analyses revealed the characteristics of ventral hippocampal CA1 (vCA1) under both physiological conditions and AD-like tau pathology. As tau progressively accumulated, vCA1, especially its excitatory and parvalbumin (PV) neurons, were fully filled with mislocated and phosphorylated tau (p-Tau). This finding was not observed for dorsal hippocampal CA1 (dCA1). The overexpression of human tau (hTau) in excitatory and PV neurons mimicked AD-like tau accumulation, significantly inhibited neuronal excitability and suppressed distinct discrimination-associated firings of these neurons within vCA1. Photoactivating excitatory and PV neurons in vCA1 at specific rhythms and time windows efficiently ameliorated tau-impaired social memory. Notably, 1 month of UA administration efficiently decreased tau accumulation via autophagy in a transcription factor EB (TFEB)-dependent manner and restored the vCA1 microcircuit to ameliorate tau-impaired social memory. CONCLUSION This study elucidated distinct protein and phosphoprotein networks between dCA1 and vCA1 and highlighted the susceptibility of the vCA1 microcircuit to AD-like tau accumulation. Notably, our novel findings regarding the efficacy of UA in reducing tau load and targeting the vCA1 microcircuit may provide a promising strategy for treating AD in the future.
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Affiliation(s)
- Hui-Yang Lei
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Gui-Lin Pi
- Department of Traditional Chinese Medicine, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China
| | - Ting He
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Rui Xiong
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jing-Ru Lv
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jia-Le Liu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dong-Qin Wu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Meng-Zhu Li
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Kun Shi
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Shi-Hong Li
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Na-Na Yu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yang Gao
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hui-Ling Yu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lin-Yu Wei
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xin Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qiu-Zhi Zhou
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Pei-Lin Zou
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jia-Yang Zhou
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Ying-Zhou Liu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Nai-Ting Shen
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jie Yang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dan Ke
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qun Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Gong-Ping Liu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xi-Fei Yang
- Key Laboratory of Modern Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, 518055, Guangdong, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226000, Jiangsu, China.
| | - Ying Yang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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18
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Kamondi A, Grigg-Damberger M, Löscher W, Tanila H, Horvath AA. Epilepsy and epileptiform activity in late-onset Alzheimer disease: clinical and pathophysiological advances, gaps and conundrums. Nat Rev Neurol 2024; 20:162-182. [PMID: 38356056 DOI: 10.1038/s41582-024-00932-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2024] [Indexed: 02/16/2024]
Abstract
A growing body of evidence has demonstrated a link between Alzheimer disease (AD) and epilepsy. Late-onset epilepsy and epileptiform activity can precede cognitive deterioration in AD by years, and its presence has been shown to predict a faster disease course. In animal models of AD, amyloid and tau pathology are linked to cortical network hyperexcitability that precedes the first signs of memory decline. Thus, detection of epileptiform activity in AD has substantial clinical importance as a potential novel modifiable risk factor for dementia. In this Review, we summarize the epidemiological evidence for the complex bidirectional relationship between AD and epilepsy, examine the effect of epileptiform activity and seizures on cognition in people with AD, and discuss the precision medicine treatment strategies based on the latest research in human and animal models. Finally, we outline some of the unresolved questions of the field that should be addressed by rigorous research, including whether particular clinicopathological subtypes of AD have a stronger association with epilepsy, and the sequence of events between epileptiform activity and amyloid and tau pathology.
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Affiliation(s)
- Anita Kamondi
- National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary.
- Department of Neurology, Semmelweis University, Budapest, Hungary.
| | | | - Wolfgang Löscher
- Department of Experimental Otology of the ENT Clinics, Hannover Medical School, Hannover, Germany
| | - Heikki Tanila
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Andras Attila Horvath
- National Institute of Mental Health, Neurology and Neurosurgery, Budapest, Hungary
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
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19
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Wodrich APK, Harris BT, Giniger E. Changes in mitochondrial distribution occur at the axon initial segment in association with neurodegeneration in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580288. [PMID: 38405730 PMCID: PMC10888798 DOI: 10.1101/2024.02.14.580288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Changes in mitochondrial distribution are a feature of numerous age-related neurodegenerative diseases. In Drosophila, reducing the activity of Cdk5 causes a neurodegenerative phenotype and is known to affect several mitochondrial properties. Therefore, we investigated whether alterations of mitochondrial distribution are involved in Cdk5-associated neurodegeneration. We find that reducing Cdk5 activity does not alter the balance of mitochondrial localization to the somatodendritic vs. axonal neuronal compartments of the mushroom body, the learning and memory center of the Drosophila brain. We do, however, observe changes in mitochondrial distribution at the axon initial segment (AIS), a neuronal compartment located in the proximal axon involved in neuronal polarization and action potential initiation. Specifically, we observe that mitochondria are partially excluded from the AIS in wild-type neurons, but that this exclusion is lost upon reduction of Cdk5 activity, concomitant with the shrinkage of the AIS domain that is known to occur in this condition. This mitochondrial redistribution into the AIS is not likely due to the shortening of the AIS domain itself but rather due to altered Cdk5 activity. Furthermore, mitochondrial redistribution into the AIS is unlikely to be an early driver of neurodegeneration in the context of reduced Cdk5 activity.
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Affiliation(s)
- Andrew P. K. Wodrich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC
- College of Medicine, University of Kentucky, Lexington, KY
| | - Brent T. Harris
- Department of Pathology, Georgetown University, Washington, DC
- Department of Neurology, Georgetown University, Washington, DC
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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Padmanabhan P, Kneynsberg A, Cruz E, Briner A, Götz J. Single-molecule imaging of Tau reveals how phosphorylation affects its movement and confinement in living cells. Mol Brain 2024; 17:7. [PMID: 38347594 PMCID: PMC10863257 DOI: 10.1186/s13041-024-01078-6] [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: 05/21/2023] [Accepted: 01/22/2024] [Indexed: 02/15/2024] Open
Abstract
Tau is a microtubule-associated protein that is regulated by post-translational modifications. The most studied of these modifications is phosphorylation, which affects Tau's aggregation and loss- and gain-of-functions, including the interaction with microtubules, in Alzheimer's disease and primary tauopathies. However, little is known about how Tau's phosphorylation state affects its dynamics and organisation at the single-molecule level. Here, using quantitative single-molecule localisation microscopy, we examined how mimicking or abrogating phosphorylation at 14 disease-associated serine and threonine residues through mutagenesis influences the behaviour of Tau in live Neuro-2a cells. We observed that both pseudohyperphosphorylated Tau (TauE14) and phosphorylation-deficient Tau (TauA14) exhibit a heterogeneous mobility pattern near the plasma membrane. Notably, we found that the mobility of TauE14 molecules was higher than wild-type Tau molecules, while TauA14 molecules displayed lower mobility. Moreover, TauA14 was organised in a filament-like structure resembling cytoskeletal filaments, within which TauA14 exhibited spatial and kinetic heterogeneity. Our study provides a direct visualisation of how the phosphorylation state of Tau affects its spatial and temporal organisation, presumably reflecting the phosphorylation-dependent changes in the interactions between Tau and its partners. We suggest that alterations in Tau dynamics resulting from aberrant changes in phosphorylation could be a critical step in its pathological dysregulation.
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Affiliation(s)
- Pranesh Padmanabhan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia.
| | - Andrew Kneynsberg
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Esteban Cruz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Adam Briner
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia
| | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, 4072, Brisbane, Australia.
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21
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Cruz E, Nisbet RM, Götz J. Break and accelerator-The mechanics of Tau (and amyloid) toxicity. Cytoskeleton (Hoboken) 2024; 81:24-29. [PMID: 37632370 DOI: 10.1002/cm.21781] [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: 06/28/2023] [Revised: 08/14/2023] [Accepted: 08/16/2023] [Indexed: 08/28/2023]
Abstract
Aggregates of the microtubule-associated protein Tau define more than a dozen primary tauopathies, and together with amyloid-β, the secondary tauopathy Alzheimer's disease (AD). Historically, Tau has been viewed as executor of amyloid-β toxicity, with the two molecules working together as "trigger and bullet." Given the two protein's opposing roles in protein translation, we wish to introduce another metaphor, borrowing from the mechanics of a car, with amyloid-β boosting Tau translation, whereas Tau puts a break on global translation. The underlying studies entail an alternative hypothesis regarding Tau's subcellular accumulation in AD, namely its de novo synthesis in the somatodendritic domain rather than the relocalization from the axon upon dissociation from microtubules. We contest that it may be worth (given Tau's 50th birthday) to revisit some entrenched dogmas about Tau's pathophysiology.
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Affiliation(s)
- Esteban Cruz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Rebecca M Nisbet
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia
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22
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Quintela-López T, Lezmy J. Homeostatic plasticity of axonal excitable sites in Alzheimer's disease. Front Neurosci 2023; 17:1277251. [PMID: 37937068 PMCID: PMC10626477 DOI: 10.3389/fnins.2023.1277251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/06/2023] [Indexed: 11/09/2023] Open
Affiliation(s)
| | - Jonathan Lezmy
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
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23
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Dan L, Zhang Z. Alzheimer's disease: an axonal injury disease? Front Aging Neurosci 2023; 15:1264448. [PMID: 37927337 PMCID: PMC10620718 DOI: 10.3389/fnagi.2023.1264448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 09/14/2023] [Indexed: 11/07/2023] Open
Abstract
Alzheimer's disease (AD) is the primary cause of dementia and is anticipated to impose a substantial economic burden in the future. Over a significant period, the widely accepted amyloid cascade hypothesis has guided research efforts, and the recent FDA approval of an anti- amyloid-beta (Aβ) protofibrils antibody, believed to decelerate AD progression, has further solidified its significance. However, the excessive emphasis placed on the amyloid cascade hypothesis has overshadowed the physiological nature of Aβ and tau proteins within axons. Axons, specialized neuronal structures, sustain damage during the early stages of AD, exerting a pivotal influence on disease progression. In this review, we present a comprehensive summary of the relationship between axonal damage and AD pathology, amalgamating the physiological roles of Aβ and tau proteins, along with the impact of AD risk genes such as APOE and TREM2. Furthermore, we underscore the exceptional significance of axonal damage in the context of AD.
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Affiliation(s)
| | - Zhaohui Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
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24
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Robles-Gómez ÁA, Ordaz B, Lorea-Hernández JJ, Peña-Ortega F. Deleterious and protective effects of epothilone-D alone and in the context of amyloid β- and tau-induced alterations. Front Mol Neurosci 2023; 16:1198299. [PMID: 37900942 PMCID: PMC10603193 DOI: 10.3389/fnmol.2023.1198299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 09/20/2023] [Indexed: 10/31/2023] Open
Abstract
Amyloid-β (Aβ) and hyperphosphorylated tau (P-tau) are Alzheimer's disease (AD) biomarkers that interact in a complex manner to induce most of the cognitive and brain alterations observed in this disease. Since the neuronal cytoskeleton is a common downstream pathological target of tau and Aβ, which mostly lead to augmented microtubule instability, the administration of microtubule stabilizing agents (MSAs) can protect against their pathological actions. However, the effectiveness of MSAs is still uncertain due to their state-dependent negative effects; thus, evaluating their specific actions in different pathological or physiological conditions is required. We evaluated whether epothilone-D (Epo-D), a clinically used MSA, rescues from the functional and behavioral alterations produced by intracerebroventricular injection of Aβ, the presence of P-tau, or their combination in rTg4510 mice. We also explored the side effects of Epo-D. To do so, we evaluated hippocampal-dependent spatial memory with the Hebb-Williams maze, hippocampal CA1 integrity and the intrinsic and synaptic properties of CA1 pyramidal neurons with the patch-clamp technique. Aβ and P-tau mildly impaired memory retrieval, but produced contrasting effects on intrinsic excitability. When Aβ and P-tau were combined, the alterations in excitability and spatial reversal learning (i.e., cognitive flexibility) were exacerbated. Interestingly, Epo-D prevented most of the impairments induced Aβ and P-tau alone and combined. However, Epo-D also exhibited some side effects depending on the prevailing pathological or physiological condition, which should be considered in future preclinical and translational studies. Although we did not perform extensive histopathological evaluations or measured microtubule stability, our findings show that MSAs can rescue the consequences of AD-like conditions but otherwise be harmful if administered at a prodromal stage of the disease.
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Affiliation(s)
- Ángel Abdiel Robles-Gómez
- Instituto de Neurobiología, UNAM Campus Juriquilla, Querétaro, Mexico
- Posgrado en Ciencias Biológicas, UNAM, Ciudad Universitaria, México City, Mexico
| | - Benito Ordaz
- Instituto de Neurobiología, UNAM Campus Juriquilla, Querétaro, Mexico
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Le LTHL, Lee J, Im D, Park S, Hwang K, Lee JH, Jiang Y, Lee Y, Suh YH, Kim HI, Lee MJ. Self-Aggregating Tau Fragments Recapitulate Pathologic Phenotypes and Neurotoxicity of Alzheimer's Disease in Mice. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2302035. [PMID: 37594721 PMCID: PMC10582461 DOI: 10.1002/advs.202302035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/10/2023] [Indexed: 08/19/2023]
Abstract
In tauopathy conditions, such as Alzheimer's disease (AD), highly soluble and natively unfolded tau polymerizes into an insoluble filament; however, the mechanistic details of this process remain unclear. In the brains of AD patients, only a minor segment of tau forms β-helix-stacked protofilaments, while its flanking regions form disordered fuzzy coats. Here, it is demonstrated that the tau AD nucleation core (tau-AC) sufficiently induced self-aggregation and recruited full-length tau to filaments. Unexpectedly, phospho-mimetic forms of tau-AC (at Ser324 or Ser356) show markedly reduced oligomerization and seeding propensities. Biophysical analysis reveal that the N-terminus of tau-AC facilitates the fibrillization kinetics as a nucleation motif, which becomes sterically shielded through phosphorylation-induced conformational changes in tau-AC. Tau-AC oligomers are efficiently internalized into cells via endocytosis and induced endogenous tau aggregation. In primary hippocampal neurons, tau-AC impaired axon initial segment plasticity upon chronic depolarization and is mislocalized to the somatodendritic compartments. Furthermore, it is observed significantly impaired memory retrieval in mice intrahippocampally injected with tau-AC fibrils, which corresponds to the neuropathological staining and neuronal loss in the brain. These findings identify tau-AC species as a key neuropathological driver in AD, suggesting novel strategies for therapeutic intervention.
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Affiliation(s)
- Ly Thi Huong Luu Le
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
| | - Jeeyoung Lee
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
- Brain Science InstituteKorea Institute of Science and TechnologySeoul02792South Korea
| | - Dongjoon Im
- Department of ChemistryKorea UniversitySeoul02841South Korea
| | - Sunha Park
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
| | - Kyoung‐Doo Hwang
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
- Department of PhysiologySeoul National University College of MedicineSeoul03080South Korea
| | - Jung Hoon Lee
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
| | - Yanxialei Jiang
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
- School of MedicineLinyi UniversityLinyi276000China
| | - Yong‐Seok Lee
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
- Department of PhysiologySeoul National University College of MedicineSeoul03080South Korea
- Neuroscience Research InstituteSeoul National University College of MedicineSeoul03080South Korea
| | - Young Ho Suh
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
- Neuroscience Research InstituteSeoul National University College of MedicineSeoul03080South Korea
| | - Hugh I. Kim
- Department of ChemistryKorea UniversitySeoul02841South Korea
| | - Min Jae Lee
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
- Ischemic/Hypoxic Disease Institute, Convergence Research Center for DementiaSeoul National University College of MedicineSeoul03080South Korea
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26
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McGregor JN, Farris CA, Ensley S, Schneider A, Wang C, Liu Y, Tu J, Elmore H, Ronayne KD, Wessel R, Dyer EL, Bhaskaran-Nair K, Holtzman DM, Hengen KB. Tauopathy severely disrupts homeostatic set-points in emergent neural dynamics but not in the activity of individual neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555947. [PMID: 37732214 PMCID: PMC10508737 DOI: 10.1101/2023.09.01.555947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The homeostatic regulation of neuronal activity is essential for robust computation; key set-points, such as firing rate, are actively stabilized to compensate for perturbations. From this perspective, the disruption of brain function central to neurodegenerative disease should reflect impairments of computationally essential set-points. Despite connecting neurodegeneration to functional outcomes, the impact of disease on set-points in neuronal activity is unknown. Here we present a comprehensive, theory-driven investigation of the effects of tau-mediated neurodegeneration on homeostatic set-points in neuronal activity. In a mouse model of tauopathy, we examine 27,000 hours of hippocampal recordings during free behavior throughout disease progression. Contrary to our initial hypothesis that tauopathy would impact set-points in spike rate and variance, we found that cell-level set-points are resilient to even the latest stages of disease. Instead, we find that tauopathy disrupts neuronal activity at the network-level, which we quantify using both pairwise measures of neuron interactions as well as measurement of the network's nearness to criticality, an ideal computational regime that is known to be a homeostatic set-point. We find that shifts in network criticality 1) track with symptoms, 2) predict underlying anatomical and molecular pathology, 3) occur in a sleep/wake dependent manner, and 4) can be used to reliably classify an animal's genotype. Our data suggest that the critical set-point is intact, but that homeostatic machinery is progressively incapable of stabilizing hippocampal networks, particularly during waking. This work illustrates how neurodegenerative processes can impact the computational capacity of neurobiological systems, and suggest an important connection between molecular pathology, circuit function, and animal behavior.
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Affiliation(s)
- James N McGregor
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Clayton A Farris
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Sahara Ensley
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Aidan Schneider
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Chao Wang
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University in Saint Louis, St. Louis, MO, USA
- Institute for Brain Science and Disease, Chongqing Medical University, 400016, Chongqing, China
| | - Yuqi Liu
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Jianhong Tu
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Halla Elmore
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Keenan D Ronayne
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
| | - Ralf Wessel
- Department of Physics, Washington University in Saint Louis, St. Louis, MO, USA
| | - Eva L Dyer
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University in Saint Louis, St. Louis, MO, USA
| | - Keith B Hengen
- Department of Biology, Washington University in Saint Louis, St. Louis, MO, USA
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27
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van Heusden FC, van Nifterick AM, Souza BC, França ASC, Nauta IM, Stam CJ, Scheltens P, Smit AB, Gouw AA, van Kesteren RE. Neurophysiological alterations in mice and humans carrying mutations in APP and PSEN1 genes. Alzheimers Res Ther 2023; 15:142. [PMID: 37608393 PMCID: PMC10464047 DOI: 10.1186/s13195-023-01287-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 08/11/2023] [Indexed: 08/24/2023]
Abstract
BACKGROUND Studies in animal models of Alzheimer's disease (AD) have provided valuable insights into the molecular and cellular processes underlying neuronal network dysfunction. Whether and how AD-related neurophysiological alterations translate between mice and humans remains however uncertain. METHODS We characterized neurophysiological alterations in mice and humans carrying AD mutations in the APP and/or PSEN1 genes, focusing on early pre-symptomatic changes. Longitudinal local field potential recordings were performed in APP/PS1 mice and cross-sectional magnetoencephalography recordings in human APP and/or PSEN1 mutation carriers. All recordings were acquired in the left frontal cortex, parietal cortex, and hippocampus. Spectral power and functional connectivity were analyzed and compared with wildtype control mice and healthy age-matched human subjects. RESULTS APP/PS1 mice showed increased absolute power, especially at higher frequencies (beta and gamma) and predominantly between 3 and 6 moa. Relative power showed an overall shift from lower to higher frequencies over almost the entire recording period and across all three brain regions. Human mutation carriers, on the other hand, did not show changes in power except for an increase in relative theta power in the hippocampus. Mouse parietal cortex and hippocampal power spectra showed a characteristic peak at around 8 Hz which was not significantly altered in transgenic mice. Human power spectra showed a characteristic peak at around 9 Hz, the frequency of which was significantly reduced in mutation carriers. Significant alterations in functional connectivity were detected in theta, alpha, beta, and gamma frequency bands, but the exact frequency range and direction of change differed for APP/PS1 mice and human mutation carriers. CONCLUSIONS Both mice and humans carrying APP and/or PSEN1 mutations show abnormal neurophysiological activity, but several measures do not translate one-to-one between species. Alterations in absolute and relative power in mice should be interpreted with care and may be due to overexpression of amyloid in combination with the absence of tau pathology and cholinergic degeneration. Future studies should explore whether changes in brain activity in other AD mouse models, for instance, those also including tau pathology, provide better translation to the human AD continuum.
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Affiliation(s)
- Fran C van Heusden
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, 1081HV, The Netherlands
| | - Anne M van Nifterick
- Alzheimer Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, Amsterdam, 1081HV, The Netherlands
- Clinical Neurophysiology and MEG Center, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, Amsterdam, 1081HV, The Netherlands
| | - Bryan C Souza
- Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, 6525AJ, The Netherlands
| | - Arthur S C França
- Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, 6525AJ, The Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, 1105 BA, The Netherlands
| | - Ilse M Nauta
- MS Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, Amsterdam, 1081HV, The Netherlands
| | - Cornelis J Stam
- Clinical Neurophysiology and MEG Center, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, Amsterdam, 1081HV, The Netherlands
| | - Philip Scheltens
- Alzheimer Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, Amsterdam, 1081HV, The Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, 1081HV, The Netherlands
| | - Alida A Gouw
- Alzheimer Center Amsterdam, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, Amsterdam, 1081HV, The Netherlands
- Clinical Neurophysiology and MEG Center, Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC Location VUmc, Amsterdam, 1081HV, The Netherlands
| | - Ronald E van Kesteren
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, 1081HV, The Netherlands.
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28
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Concepcion FA, Ekstrom NA, Khan MN, Estes OO, Poolos NP. Progressive Dysregulation of Tau Phosphorylation in an Animal Model of Temporal Lobe Epilepsy. Neuroscience 2023; 522:42-56. [PMID: 37142182 PMCID: PMC10330640 DOI: 10.1016/j.neuroscience.2023.04.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 04/22/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023]
Abstract
Tau is an intracellular protein known to undergo hyperphosphorylation and subsequent neuro-toxic aggregation in Alzheimer's disease (AD). Here, tau expression and phosphorylation at three canonical loci known to be hyperphosphorylated in AD (S202/T205, T181, and T231) were studied in the rat pilocarpine status epilepticus (SE) model of temporal lobe epilepsy (TLE). We measured tau expression at two time points of chronic epilepsy: two months and four months post-SE. Both time points parallel human TLE of at least several years. In the whole hippocampal formation at two months post-SE, we observed modestly reduced total tau levels compared to naïve controls, but no significant reduction in S202/T205 phosphorylation levels. In the whole hippocampal formation from four month post-SE rats, total tau expression had reverted to normal, but there was a significant reduction in S202/T205 tau phosphorylation levels that was also seen in CA1 and CA3. No change in phosphorylation was seen at the T181 and T231 tau loci. In somatosensory cortex, outside of the seizure onset zone, no changes in tau expression or phosphorylation were seen at the later time point. We conclude that total tau expression and phosphorylation in an animal model of TLE do not show hyperphosphorylation at the three AD canonical tau loci. Instead, the S202/T205 locus showed progressive dephosphorylation. This suggests that changes in tau expression may play a different role in epilepsy than in AD. Further study is needed to understand how these changes in tau may impact neuronal excitability in chronic epilepsy.
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Affiliation(s)
- F A Concepcion
- Department of Neurology and Regional Epilepsy Center, University of Washington, Seattle, WA, United States
| | - N A Ekstrom
- Department of Neurology and Regional Epilepsy Center, University of Washington, Seattle, WA, United States
| | - M N Khan
- Department of Neurology and Regional Epilepsy Center, University of Washington, Seattle, WA, United States
| | - O O Estes
- Department of Neurology and Regional Epilepsy Center, University of Washington, Seattle, WA, United States
| | - N P Poolos
- Department of Neurology and Regional Epilepsy Center, University of Washington, Seattle, WA, United States.
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29
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Best MN, Lim Y, Ferenc NN, Kim N, Min L, Wang DB, Sharifi K, Wasserman AE, McTavish SA, Siller KH, Jones MK, Jenkins PM, Mandell JW, Bloom GS. Extracellular Tau Oligomers Damage the Axon Initial Segment. J Alzheimers Dis 2023:JAD221284. [PMID: 37182881 DOI: 10.3233/jad-221284] [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 In Alzheimer's disease (AD) brain, neuronal polarity and synaptic connectivity are compromised. A key structure for regulating polarity and functions of neurons is the axon initial segment (AIS), which segregates somatodendritic from axonal proteins and initiates action potentials. Toxic tau species, including extracellular oligomers (xcTauOs), spread tau pathology from neuron to neuron by a prion-like process, but few other cell biological effects of xcTauOs have been described. OBJECTIVE Test the hypothesis that AIS structure is sensitive to xcTauOs. METHODS Cultured wild type (WT) and tau knockout (KO) mouse cortical neurons were exposed to xcTauOs, and quantitative western blotting and immunofluorescence microscopy with anti-TRIM46 monitored effects on the AIS. The same methods were used to compare TRIM46 and two other resident AIS proteins in human hippocampal tissue obtained from AD and age-matched non-AD donors. RESULTS Without affecting total TRIM46 levels, xcTauOs reduce the concentration of TRIM46 within the AIS and cause AIS shortening in cultured WT, but not TKO neurons. Lentiviral-driven tau expression in tau KO neurons rescues AIS length sensitivity to xcTauOs. In human AD hippocampus, the overall protein levels of multiple resident AIS proteins are unchanged compared to non-AD brain, but TRIM46 concentration within the AIS and AIS length are reduced in neurons containing neurofibrillary tangles. CONCLUSION xcTauOs cause partial AIS damage in cultured neurons by a mechanism dependent on intracellular tau, thereby raising the possibility that the observed AIS reduction in AD neurons in vivo is caused by xcTauOs working in concert with endogenous neuronal tau.
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Affiliation(s)
- Merci N Best
- Department of Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Yunu Lim
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Nina N Ferenc
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Nayoung Kim
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Lia Min
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Dora Bigler Wang
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Kamyar Sharifi
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Anna E Wasserman
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Sloane A McTavish
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Karsten H Siller
- Research Computing, University of Virginia, Charlottesville, VA, USA
| | - Marieke K Jones
- Claude Moore Health Sciences Library, University of Virginia, Charlottesville, VA, USA
| | - Paul M Jenkins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - James W Mandell
- Department of Pathology, University of Virginia, Charlottesville, VA, USA
| | - George S Bloom
- Department of Biology, University of Virginia, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
- Department of Neuroscience, University of Virginia, Charlottesville, VA, USA
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Padmanabhan P, Götz J. Clinical relevance of animal models in aging-related dementia research. NATURE AGING 2023; 3:481-493. [PMID: 37202516 DOI: 10.1038/s43587-023-00402-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 03/21/2023] [Indexed: 05/20/2023]
Abstract
Alzheimer's disease (AD) and other, less prevalent dementias are complex age-related disorders that exhibit multiple etiologies. Over the past decades, animal models have provided pathomechanistic insight and evaluated countless therapeutics; however, their value is increasingly being questioned due to the long history of drug failures. In this Perspective, we dispute this criticism. First, the utility of the models is limited by their design, as neither the etiology of AD nor whether interventions should occur at a cellular or network level is fully understood. Second, we highlight unmet challenges shared between animals and humans, including impeded drug transport across the blood-brain barrier, limiting effective treatment development. Third, alternative human-derived models also suffer from the limitations mentioned above and can only act as complementary resources. Finally, age being the strongest AD risk factor should be better incorporated into the experimental design, with computational modeling expected to enhance the value of animal models.
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Affiliation(s)
- Pranesh Padmanabhan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, the University of Queensland, Brisbane, Queensland, Australia
| | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, the University of Queensland, Brisbane, Queensland, Australia.
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Parka A, Volbracht C, Hall B, Bastlund JF, Nedergaard M, Laursen B, Botta P, Sotty F. Visual Evoked Potentials as an Early-Stage Biomarker in the rTg4510 Tauopathy Mouse Model. J Alzheimers Dis 2023; 93:247-262. [PMID: 37005884 DOI: 10.3233/jad-220964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Background: Tauopathies such as Alzheimer’s disease (AD) and frontotemporal dementia (FTD) are characterized by formation of neurofibrillary tangles consisting of hyperphosphorylated tau protein. Early pathophysiological and functional changes related to neurofibrillary tangles formation are considered to occur prior to extensive neurodegeneration. Hyperphosphorylated tau has been detected in postmortem retinas of AD and FTD patients, and the visual pathway is an easily accessible system in a clinical setting. Hence, assessment of the visual function may offer the potential to detect consequences of early tau pathology in patients. Objective: The aim of this study was to evaluate visual function in a tauopathy mouse model in relation to tau hyperphosphorylation and neurodegeneration. Methods: In this study we explored the association between the visual system and functional consequences of tau pathology progression using a tauopathy rTg4510 mouse model. To this end, we recorded full-field electroretinography and visual evoked potentials in anesthetized and awake states at different ages. Results: While retinal function remained mostly intact within all the age groups investigated, we detected significant changes in amplitudes of visual evoked potential responses in young rTg4510 mice exhibiting early tau pathology prior to neurodegeneration. These functional alterations in the visual cortex were positively correlated with pathological tau levels. Conclusion: Our findings suggest that visual processing could be useful as a novel electrophysiological biomarker for early stages of tauopathy.
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Affiliation(s)
- Aleksandra Parka
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
- H. Lundbeck A/S, Research, Valby, Denmark
| | | | | | | | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
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Boal AM, McGrady NR, Holden JM, Risner ML, Calkins DJ. Retinal ganglion cells adapt to ionic stress in experimental glaucoma. Front Neurosci 2023; 17:1142668. [PMID: 37051140 PMCID: PMC10083336 DOI: 10.3389/fnins.2023.1142668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/10/2023] [Indexed: 03/28/2023] Open
Abstract
IntroductionIdentification of early adaptive and maladaptive neuronal stress responses is an important step in developing targeted neuroprotective therapies for degenerative disease. In glaucoma, retinal ganglion cells (RGCs) and their axons undergo progressive degeneration resulting from stress driven by sensitivity to intraocular pressure (IOP). Despite therapies that can effectively manage IOP many patients progress to vision loss, necessitating development of neuronal-based therapies. Evidence from experimental models of glaucoma indicates that early in the disease RGCs experience altered excitability and are challenged with dysregulated potassium (K+) homeostasis. Previously we demonstrated that certain RGC types have distinct excitability profiles and thresholds for depolarization block, which are associated with sensitivity to extracellular K+.MethodsHere, we used our inducible mouse model of glaucoma to investigate how RGC sensitivity to K+ changes with exposure to elevated IOP.ResultsIn controls, conditions of increased K+ enhanced membrane depolarization, reduced action potential generation, and widened action potentials. Consistent with our previous work, 4 weeks of IOP elevation diminished RGC light-and current-evoked responses. Compared to controls, we found that IOP elevation reduced the effects of increased K+ on depolarization block threshold, with IOP-exposed cells maintaining greater excitability. Finally, IOP elevation did not alter axon initial segment dimensions, suggesting that structural plasticity alone cannot explain decreased K+ sensitivity.DiscussionThus, in response to prolonged IOP elevation RGCs undergo an adaptive process that reduces sensitivity to changes in K+ while diminishing excitability. These experiments give insight into the RGC response to IOP stress and lay the groundwork for mechanistic investigation into targets for neuroprotective therapy.
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Hatch RJ, Berecki G, Jancovski N, Li M, Rollo B, Jafar-Nejad P, Rigo F, Kaila K, Reid CA, Petrou S. Carbogen-Induced Respiratory Acidosis Blocks Experimental Seizures by a Direct and Specific Inhibition of Na V1.2 Channels in the Axon Initial Segment of Pyramidal Neurons. J Neurosci 2023; 43:1658-1667. [PMID: 36732074 PMCID: PMC10010452 DOI: 10.1523/jneurosci.1387-22.2022] [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: 07/18/2022] [Revised: 11/01/2022] [Accepted: 12/05/2022] [Indexed: 02/04/2023] Open
Abstract
Brain pH is a critical factor for determining neuronal activity, with alkalosis increasing and acidosis reducing excitability. Acid shifts in brain pH through the breathing of carbogen (5% CO2/95% O2) reduces seizure susceptibility in animal models and patients. The molecular mechanisms underlying this seizure protection remain to be fully elucidated. Here, we demonstrate that male and female mice exposed to carbogen are fully protected from thermogenic-triggered seizures. Whole-cell patch-clamp recordings revealed that acid shifts in extracellular pH (pHo) significantly reduce action potential firing in CA1 pyramidal neurons but did not alter firing in hippocampal inhibitory interneurons. In real-time dynamic clamp experiments, acidification reduced simulated action potential firing generated in hybrid model neurons expressing the excitatory neuron predominant NaV1.2 channel. Conversely, acidification had no effect on action potential firing in hybrid model neurons expressing the interneuron predominant NaV1.1 channel. Furthermore, knockdown of Scn2a mRNA in vivo using antisense oligonucleotides reduced the protective effects of carbogen on seizure susceptibility. Both carbogen-mediated seizure protection and the reduction in CA1 pyramidal neuron action potential firing by low pHo were maintained in an Asic1a knock-out mouse ruling out this acid-sensing channel as the underlying molecular target. These data indicate that the acid-mediated reduction in excitatory neuron firing is mediated, at least in part, through the inhibition of NaV1.2 channels, whereas inhibitory neuron firing is unaffected. This reduction in pyramidal neuron excitability is the likely basis of seizure suppression caused by carbogen-mediated acidification.SIGNIFICANCE STATEMENT Brain pH has long been known to modulate neuronal excitability. Here, we confirm that brain acidification reduces seizure susceptibility in a mouse model of thermogenic seizures. Extracellular acidification reduced excitatory pyramidal neuron firing while having no effect on interneuron firing. Acidification also reduced dynamic clamp firing in cells expressing the NaV1.2 channel but not in cells expressing NaV1.1 channels. In vivo knockdown of Scn2a mRNA reduced seizure protection of acidification. In contrast, acid-mediated seizure protection was maintained in the Asic1a knock-out mouse. These data suggest NaV1.2 channel as an important target for acid-mediated seizure protection. Our results have implications on how natural variations in pH can modulate neuronal excitability and highlight potential antiseizure drug development strategies based on the NaV1.2 channel.
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Affiliation(s)
- Robert J Hatch
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Géza Berecki
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Nikola Jancovski
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Melody Li
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Ben Rollo
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California 92008
| | - Kai Kaila
- Molecular and Integrative Biosciences and Neuroscience Center, University of Helsinki, 00014 Helsinki, Finland
| | - Christopher A Reid
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
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Early impairments of visually-driven neuronal ensemble dynamics in the rTg4510 tauopathy mouse model. Neurobiol Dis 2023; 178:106012. [PMID: 36696792 DOI: 10.1016/j.nbd.2023.106012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/24/2023] Open
Abstract
Tau protein pathology is a hallmark of many neurodegenerative diseases, including Alzheimer's Disease or frontotemporal dementia. Synaptic dysfunction and abnormal visual evoked potentials have been reported in murine models of tauopathy, but little is known about the state of the network activity on a single neuronal level prior to brain atrophy. In the present study, oscillatory rhythms and single-cell calcium activity of primary visual cortex pyramidal neuron population were investigated in basal and light evoked states in the rTg4510 tauopathy mouse model prior to neurodegeneration. We found a decrease in their responsivity and overall activity which was insensitive to GABAergic modulation. Despite an enhancement of basal state coactivation of cortical pyramidal neurons, a loss of input-output synchronicity was observed. Dysfunction of cortical pyramidal function was also reflected in a reduction of basal theta oscillations and enhanced susceptibility to a sub-convulsive dose of pentylenetetrazol in rTg4510 mice. Our results unveil impairments in visual cortical pyramidal neuron processing and define aberrant oscillations as biomarker candidates in early stages of neurodegenerative tauopathies.
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Alexandersen CG, de Haan W, Bick C, Goriely A. A multi-scale model explains oscillatory slowing and neuronal hyperactivity in Alzheimer's disease. J R Soc Interface 2023; 20:20220607. [PMID: 36596460 PMCID: PMC9810432 DOI: 10.1098/rsif.2022.0607] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Alzheimer's disease is the most common cause of dementia and is linked to the spreading of pathological amyloid-β and tau proteins throughout the brain. Recent studies have highlighted stark differences in how amyloid-β and tau affect neurons at the cellular scale. On a larger scale, Alzheimer's patients are observed to undergo a period of early-stage neuronal hyperactivation followed by neurodegeneration and frequency slowing of neuronal oscillations. Herein, we model the spreading of both amyloid-β and tau across a human connectome and investigate how the neuronal dynamics are affected by disease progression. By including the effects of both amyloid-β and tau pathology, we find that our model explains AD-related frequency slowing, early-stage hyperactivation and late-stage hypoactivation. By testing different hypotheses, we show that hyperactivation and frequency slowing are not due to the topological interactions between different regions but are mostly the result of local neurotoxicity induced by amyloid-β and tau protein.
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Affiliation(s)
| | - Willem de Haan
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
| | - Christian Bick
- Mathematical Institute, University of Oxford, Oxford, UK,Department of Mathematics, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands,Amsterdam Neuroscience—Systems and Network Neuroscience, Amsterdam, The Netherlands
| | - Alain Goriely
- Mathematical Institute, University of Oxford, Oxford, UK
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36
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Lehmann DJ, Elshorbagy A, Hurley MJ. Many Paths to Alzheimer's Disease: A Unifying Hypothesis Integrating Biological, Chemical, and Physical Risk Factors. J Alzheimers Dis 2023; 95:1371-1382. [PMID: 37694367 DOI: 10.3233/jad-230295] [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: 09/12/2023]
Abstract
Sporadic Alzheimer's disease (AD) is a complex, multifactorial disease. We should therefore expect to find many factors involved in its causation. The known neuropathology seen at autopsy in patients dying with AD is not consistently seen in all patients with AD and is sometimes seen in patients without dementia. This suggests that patients follow different paths to AD, with different people having slightly different combinations of predisposing physical, chemical and biologic risk factors, and varying neuropathology. This review summarizes what is known of the biologic and chemical predisposing factors and features in AD. We postulate that, underlying the neuropathology of AD is a progressive failure of neurons, with advancing age or other morbidity, to rid themselves of entropy, i.e., the disordered state resulting from brain metabolism. Understanding the diverse causes of AD may allow the development of new therapies targeted at blocking the paths that lead to dementia in each subset of patients.
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Affiliation(s)
- Donald J Lehmann
- Oxford Project to Investigate Memory and Ageing (OPTIMA), Department of Pharmacology, University of Oxford, Oxford, UK
| | - Amany Elshorbagy
- Department of Pharmacology, University of Oxford, Oxford, UK
- Department of Physiology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Michael J Hurley
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
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Senol AD, Pinto G, Beau M, Guillemot V, Dupree JL, Stadelmann C, Ranft J, Lubetzki C, Davenne M. Alterations of the axon initial segment in multiple sclerosis grey matter. Brain Commun 2022; 4:fcac284. [PMID: 36451656 PMCID: PMC9700164 DOI: 10.1093/braincomms/fcac284] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 07/14/2022] [Accepted: 11/02/2022] [Indexed: 07/22/2023] Open
Abstract
Grey matter damage has been established as a key contributor to disability progression in multiple sclerosis. Aside from neuronal loss and axonal transections, which predominate in cortical demyelinated lesions, synaptic alterations have been detected in both demyelinated plaques and normal-appearing grey matter, resulting in functional neuronal damage. The axon initial segment is a key element of neuronal function, responsible for action potential initiation and maintenance of neuronal polarity. Despite several reports of profound axon initial segment alterations in different pathological models, among which experimental auto-immune encephalomyelitis, whether the axon initial segment is affected in multiple sclerosis is still unknown. Using immunohistochemistry, we analysed axon initial segments from control and multiple sclerosis tissue, focusing on layer 5/6 pyramidal neurons in the neocortex and Purkinje cells in the cerebellum and performed analysis on the parameters known to control neuronal excitability, i.e. axon initial segment length and position. We found that the axon initial segment length was increased only in pyramidal neurons of inactive demyelinated lesions, compared with normal appearing grey matter tissue. In contrast, in both cell types, the axon initial segment position was altered, with an increased soma-axon initial segment gap, in both active and inactive demyelinated lesions. In addition, using a computational model, we show that this increased gap between soma and axon initial segment might increase neuronal excitability. Taken together, these results show, for the first time, changes of axon initial segments in multiple sclerosis, in active as well as inactive grey matter lesions in both neocortex and cerebellum, which might alter neuronal function.
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Affiliation(s)
- Aysegul Dilsizoglu Senol
- Sorbonne University, Paris Brain Institute—ICM, Inserm, CNRS, Pitié-Salpêtrière Hospital, Paris, France
| | - Giulia Pinto
- Sorbonne University, Paris Brain Institute—ICM, Inserm, CNRS, Pitié-Salpêtrière Hospital, Paris, France
| | - Maxime Beau
- Institut de Biologie de l’École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris, France
| | - Vincent Guillemot
- Sorbonne University, Paris Brain Institute—ICM, Inserm, CNRS, Pitié-Salpêtrière Hospital, Paris, France
- Institut Pasteur, Université de Paris, Bioinformatics and Biostatistics Hub, Paris F-75015, France
| | - Jeffrey L Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA
- Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA
| | - Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen 37075, Germany
| | - Jonas Ranft
- Institut de Biologie de l’École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris, France
| | - Catherine Lubetzki
- Sorbonne University, Paris Brain Institute—ICM, Inserm, CNRS, Pitié-Salpêtrière Hospital, Paris, France
- Assistance Publique des Hôpitaux de Paris (APHP), Pitié-Salpêtrière Hospital, DMU Neurosciences, Paris, France
| | - Marc Davenne
- Correspondence to: Dr Marc Davenne Paris Brain Institute, Pitié-Salpêtrière Hospital 47, bd de l’hôpital, F-75013 Paris, France E-mail:
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Chockanathan U, Padmanabhan K. From synapses to circuits and back: Bridging levels of understanding in animal models of Alzheimer's disease. Eur J Neurosci 2022; 56:5564-5586. [PMID: 35244297 PMCID: PMC10926359 DOI: 10.1111/ejn.15636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/04/2022] [Accepted: 02/23/2022] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by behavioural changes that include memory loss and cognitive decline and is associated with the appearance of amyloid-β plaques and neurofibrillary tangles throughout the brain. Although aspects of the disease percolate across multiple levels of neuronal organization, from the cellular to the behavioural, it is increasingly clear that circuits are a critical junction between the cellular pathology and the behavioural phenotypes that bookend these levels of analyses. In this review, we discuss critical aspects of neural circuit research, beginning with synapses and progressing to network activity and how they influence our understanding of disease processed in AD.
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Affiliation(s)
- Udaysankar Chockanathan
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Neuroscience Graduate Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Medical Scientist Training Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Krishnan Padmanabhan
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Neuroscience Graduate Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Medical Scientist Training Program, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Center for Visual Science, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- Intellectual and Developmental Disabilities Research Center, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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Saroja SR, Sharma A, Hof PR, Pereira AC. Differential expression of tau species and the association with cognitive decline and synaptic loss in Alzheimer's disease. Alzheimers Dement 2022; 18:1602-1615. [PMID: 34873815 PMCID: PMC9170833 DOI: 10.1002/alz.12518] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 10/03/2021] [Accepted: 10/13/2021] [Indexed: 01/24/2023]
Abstract
Pathological tau proteins in patients with Alzheimer's disease (AD) mainly accumulate in the form of neurofibrillary tangles (NFTs) and neuritic plaques (NPs). However, the molecular properties of tau species present in NFTs and NPs are not known. We tested the hypothesis that tau species within NFT-predominant tissue (NFT_AD) are distinct and more toxic than those in NP-predominant tissue (NP_AD). We analyzed the tau species from post mortem prefrontal cortical brains of NFT_AD and NP_AD. Compared to NP_AD, NFT_AD displayed highly phosphorylated tau oligomers, possessed tau oligomers in extracellular vesicles, and the 3-repeat (3R) and 4-repeat (4R) isoforms were differentially expressed between the groups. Comparison of tau proteins isolated from NFT- versus NP-AD subjects demonstrated higher tau seeding activity in NFT subjects and a greater degree of inducing synaptic loss in cultured neurons. We propose that tau species from NFT-predominant tissues possess greater levels of degenerative properties, thereby causing synaptic loss and cognitive decline.
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Affiliation(s)
- Sivaprakasam R. Saroja
- Department of Neurology, Icahn School of MedicineMount SinaiNew YorkNew YorkUSA
- Nash Family Department of Neuroscience and Friedman Brain InstituteIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Abhijeet Sharma
- Department of Neurology, Icahn School of MedicineMount SinaiNew YorkNew YorkUSA
- Nash Family Department of Neuroscience and Friedman Brain InstituteIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Patrick R. Hof
- Nash Family Department of Neuroscience and Friedman Brain InstituteIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
- Ronald M. Loeb Center for Alzheimer's DiseaseIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Ana C. Pereira
- Department of Neurology, Icahn School of MedicineMount SinaiNew YorkNew YorkUSA
- Nash Family Department of Neuroscience and Friedman Brain InstituteIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
- Ronald M. Loeb Center for Alzheimer's DiseaseIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
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Zamani N, Moazedi AA, Afarinesh Khaki MR, Pourmehdi Boroujeni M. Effects of Memantine on the Spontaneous Firing Frequency of Hippocampal CA1 Pyramidal Neurons in Intact and Alzheimer Rat Model: An Electrophysiological Study. Basic Clin Neurosci 2022; 13:661-674. [PMID: 37313029 PMCID: PMC10258597 DOI: 10.32598/bcn.2021.1970.1] [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: 08/05/2019] [Revised: 02/05/2020] [Accepted: 04/19/2020] [Indexed: 11/02/2023] Open
Abstract
Introduction Memantine (MEM) is a noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonist clinically used for the treatment of Alzheimer disease (AD) in mild to severe conditions. The present study was conducted to investigate the effects of memantine on the spontaneous firing frequency of CA1 pyramidal neurons in rats caused by an electrical lesion of Nucleus Basalis Magnocellularis (NBM). Then, this model of AD rats was compared with the intact adult male rats. Methods In this study, adult male rats were divided into two groups. Group I (lesion of NBM, n=53) includes the following subgroups: lesion+saline, sham+saline, lesion+MEM 5 mg/kg, lesion+MEM 10 mg/kg, and lesion+MEM 20mg/kg. Group II (intact, n=48) includes the following subgroups: intact+saline, intact+MEM 3mg/kg, intact+MEM 5mg/kg, and intact+MEM 10mg/kg. Extracellular single-unit recording (15 min baseline+105 min after MEM or saline) was performed under urethane-anesthetized rats. Results The results showed that the mean frequency of CA1 pyramidal neurons after saline in the lesion+saline (P<0.001) group significantly decreases compared with the intact+saline and sham+saline groups. In addition, after saline and memantine, the mean frequency of CA1 pyramidal neurons in the lesion+MEM 10 mg/kg (P<0.01) and lesion+MEM 20 mg/kg (P<0.001) groups significantly increased compared with the lesion+saline group. Also, the mean frequencies of CA1 pyramidal neurons in the intact+MEM 10 mg/kg (P<0.001) group significantly decreased compared with the intact+saline group. Conclusion Results showed that memantine increases the electrical activity of CA1 pyramidal neurons in a rat model of AD. Furthermore, in the intact adult male rats, the low-dose memantine, contrary to high dose, does not decrease the electrical activity of CA1 pyramidal neurons.
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Affiliation(s)
- Nastaran Zamani
- Department of Biology, School of Science, Payame Noor University, Tehran, Iran
| | - Ahmad Ali Moazedi
- Department of Biology, School of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
- Stem Cell and Transgenic Technology Research Center, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Mohamad Reza Afarinesh Khaki
- Kerman Cognitive Research Center, Kerman Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran
| | - Mehdi Pourmehdi Boroujeni
- Department of Food Hygiene, School of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
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Yang H, Li J, Li X, Ma L, Hou M, Zhou H, Zhou R. Based on molecular structures: Amyloid-β generation, clearance, toxicity and therapeutic strategies. Front Mol Neurosci 2022; 15:927530. [PMID: 36117918 PMCID: PMC9470852 DOI: 10.3389/fnmol.2022.927530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
Amyloid-β (Aβ) has long been considered as one of the most important pathogenic factors in Alzheimer’s disease (AD), but the specific pathogenic mechanism of Aβ is still not completely understood. In recent years, the development of structural biology technology has led to new understandings about Aβ molecular structures, Aβ generation and clearance from the brain and peripheral tissues, and its pathological toxicity. The purpose of the review is to discuss Aβ metabolism and toxicity, and the therapeutic strategy of AD based on the latest progress in molecular structures of Aβ. The Aβ structure at the atomic level has been analyzed, which provides a new and refined perspective to comprehend the role of Aβ in AD and to formulate therapeutic strategies of AD.
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Affiliation(s)
- Hai Yang
- Department of Neurology, Army Medical Center of PLA, Chongqing, China
| | - Jinping Li
- Department of Neurology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China
| | - Xiaoxiong Li
- Department of Neurology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China
| | - Linqiu Ma
- Department of Neurology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China
| | - Mingliang Hou
- Department of Neurology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China
| | - Huadong Zhou
- Department of Neurology, Army Medical Center of PLA, Chongqing, China
| | - Rui Zhou
- Southwest Hospital, Army Medical University, Chongqing, China
- *Correspondence: Rui Zhou,
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Zhao W, Wang J, Latta M, Wang C, Liu Y, Ma W, Zhou Z, Hu S, Chen P, Liu Y. Rhizoma Gastrodiae Water Extract Modulates the Gut Microbiota and Pathological Changes of P-TauThr231 to Protect Against Cognitive Impairment in Mice. Front Pharmacol 2022; 13:903659. [PMID: 35910384 PMCID: PMC9335362 DOI: 10.3389/fphar.2022.903659] [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: 03/24/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022] Open
Abstract
Gastrodiae Rhizoma and its active constituents are known to exhibit neuroprotective effects in Alzheimer’s disease (AD). However, the effect of Rhizoma Gastrodiae water extract (WERG) on AD and the detailed mechanism of action remain unclear. In this study, the mechanism of action of WERG was investigated by the microbiome–gut–brain axis using a D-galactose (D-gal)/AlCl3-induced AD mouse model. WERG improved the cognitive impairment of D-gal/AlCl3-induced mice. The expression level of p-Tauthr231 in the WERG-H treatment group was decreased, and p-Tauthr231 was found negative in hippocampal DG, CA1, and CA3 regions. Here, the diversity and composition of the gut microbiota were analyzed by 16sRNA sequencing. WERG-H treatment had a positive correlation with Firmicutes, Bacilli, Lactobacillus johnsonii, Lactobacillus murinus, and Lactobacillus reuteri. Interestingly, the Rikenellaceae-RC9 gut group in the gut increased in D-gal/AlCl3-induced mice, but the increased L. johnsonii, L. murinus, and L. reuteri reversed this process. This may be a potential mechanistic link between gut microbiota dysbiosis and P-TauThr231 levels in AD progression. In conclusion, this study demonstrated that WERG improved the cognitive impairment of the AD mouse model by enriching gut probiotics and reducing P-TauThr231 levels.
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Affiliation(s)
- Wenbin Zhao
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Jianhui Wang
- Department of Pathology, Yale University School of Medicine, New Haven, CT, United States
| | - Maria Latta
- School of Pharmacy, University of Connecticut, Mansfield, CT, United States
| | - Chenyu Wang
- School of Basic Medical Science, Lanzhou University, Lanzhou, China
| | - Yuheng Liu
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Wantong Ma
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Zhongkun Zhou
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Shujian Hu
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Peng Chen
- School of Pharmacy, Lanzhou University, Lanzhou, China
- *Correspondence: Peng Chen, ; Yingqian Liu,
| | - Yingqian Liu
- School of Pharmacy, Lanzhou University, Lanzhou, China
- *Correspondence: Peng Chen, ; Yingqian Liu,
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Targa Dias Anastacio H, Matosin N, Ooi L. Neuronal hyperexcitability in Alzheimer's disease: what are the drivers behind this aberrant phenotype? Transl Psychiatry 2022; 12:257. [PMID: 35732622 PMCID: PMC9217953 DOI: 10.1038/s41398-022-02024-7] [Citation(s) in RCA: 156] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/01/2022] [Accepted: 06/08/2022] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder leading to loss of cognitive abilities and ultimately, death. With no cure available, limited treatments mostly focus on symptom management. Identifying early changes in the disease course may provide new therapeutic targets to halt or reverse disease progression. Clinical studies have shown that cortical and hippocampal hyperactivity are a feature shared by patients in the early stages of disease, progressing to hypoactivity during later stages of neurodegeneration. The exact mechanisms causing neuronal excitability changes are not fully characterized; however, animal and cell models have provided insights into some of the factors involved in this phenotype. In this review, we summarize the evidence for neuronal excitability changes over the course of AD onset and progression and the molecular mechanisms underpinning these differences. Specifically, we discuss contributors to aberrant neuronal excitability, including abnormal levels of intracellular Ca2+ and glutamate, pathological amyloid β (Aβ) and tau, genetic risk factors, including APOE, and impaired inhibitory interneuron and glial function. In light of recent research indicating hyperexcitability could be a predictive marker of cognitive dysfunction, we further argue that the hyperexcitability phenotype could be leveraged to improve the diagnosis and treatment of AD, and present potential targets for future AD treatment development.
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Affiliation(s)
- Helena Targa Dias Anastacio
- grid.510958.0Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia ,grid.1007.60000 0004 0486 528XMolecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Natalie Matosin
- grid.510958.0Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia ,grid.1007.60000 0004 0486 528XMolecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia. .,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia.
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Pyramidal cell axon initial segment in Alzheimer´s disease. Sci Rep 2022; 12:8722. [PMID: 35610289 PMCID: PMC9130508 DOI: 10.1038/s41598-022-12700-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 05/09/2022] [Indexed: 11/08/2022] Open
Abstract
The axon initial segment (AIS) is a region of the neuron that is critical for action potential generation as well as for the regulation of neural activity. This specialized structure-characterized by the expression of different types of ion channels as well as adhesion, scaffolding and cytoskeleton proteins-is subjected to morpho-functional plastic changes in length and position upon variations in neural activity or in pathological conditions. In the present study, using immunocytochemistry with the AT8 antibody (phospho-tau S202/T205) and 3D confocal microscopy reconstruction techniques in brain tissue from Alzheimer's disease patients, we found that around half of the cortical pyramidal neurons with hyperphosphorylated tau showed changes in AIS length and position in comparison with AT8-negative neurons from the same cortical layers. We observed a wide variety of AIS alterations in neurons with hyperphosphorylated tau, although the most common changes were a proximal shift or a lengthening of the AISs. Similar results were found in neocortical tissue from non-demented cases with neurons containing hyperphosphorylated tau. These findings support the notion that the accumulation of phospho-tau is associated with structural alterations of the AIS that are likely to have an impact on normal neuronal activity, which might contribute to neuronal dysfunction in AD.
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Sanchez-Varo R, Mejias-Ortega M, Fernandez-Valenzuela JJ, Nuñez-Diaz C, Caceres-Palomo L, Vegas-Gomez L, Sanchez-Mejias E, Trujillo-Estrada L, Garcia-Leon JA, Moreno-Gonzalez I, Vizuete M, Vitorica J, Baglietto-Vargas D, Gutierrez A. Transgenic Mouse Models of Alzheimer's Disease: An Integrative Analysis. Int J Mol Sci 2022; 23:5404. [PMID: 35628216 PMCID: PMC9142061 DOI: 10.3390/ijms23105404] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/10/2022] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) constitutes the most prominent form of dementia among elderly individuals worldwide. Disease modeling using murine transgenic mice was first initiated thanks to the discovery of heritable mutations in amyloid precursor protein (APP) and presenilins (PS) genes. However, due to the repeated failure of translational applications from animal models to human patients, along with the recent advances in genetic susceptibility and our current understanding on disease biology, these models have evolved over time in an attempt to better reproduce the complexity of this devastating disease and improve their applicability. In this review, we provide a comprehensive overview about the major pathological elements of human AD (plaques, tauopathy, synaptic damage, neuronal death, neuroinflammation and glial dysfunction), discussing the knowledge that available mouse models have provided about the mechanisms underlying human disease. Moreover, we highlight the pros and cons of current models, and the revolution offered by the concomitant use of transgenic mice and omics technologies that may lead to a more rapid improvement of the present modeling battery.
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Affiliation(s)
- Raquel Sanchez-Varo
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
| | - Marina Mejias-Ortega
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Juan Jose Fernandez-Valenzuela
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Cristina Nuñez-Diaz
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Laura Caceres-Palomo
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Laura Vegas-Gomez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Elisabeth Sanchez-Mejias
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Laura Trujillo-Estrada
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Juan Antonio Garcia-Leon
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Ines Moreno-Gonzalez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
- Department of Neurology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Marisa Vizuete
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
- Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Instituto de Biomedicina de Sevilla (IBIS)-Hospital Universitario Virgen del Rocio/CSIC, 41012 Seville, Spain
| | - Javier Vitorica
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
- Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Instituto de Biomedicina de Sevilla (IBIS)-Hospital Universitario Virgen del Rocio/CSIC, 41012 Seville, Spain
| | - David Baglietto-Vargas
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
| | - Antonia Gutierrez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (R.S.-V.); (M.M.-O.); (J.J.F.-V.); (C.N.-D.); (L.C.-P.); (L.V.-G.); (E.S.-M.); (L.T.-E.); (J.A.G.-L.); (I.M.-G.)
- Centro de Investigacion Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain; (M.V.); (J.V.)
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Procès A, Luciano M, Kalukula Y, Ris L, Gabriele S. Multiscale Mechanobiology in Brain Physiology and Diseases. Front Cell Dev Biol 2022; 10:823857. [PMID: 35419366 PMCID: PMC8996382 DOI: 10.3389/fcell.2022.823857] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 03/08/2022] [Indexed: 12/11/2022] Open
Abstract
Increasing evidence suggests that mechanics play a critical role in regulating brain function at different scales. Downstream integration of mechanical inputs into biochemical signals and genomic pathways causes observable and measurable effects on brain cell fate and can also lead to important pathological consequences. Despite recent advances, the mechanical forces that influence neuronal processes remain largely unexplored, and how endogenous mechanical forces are detected and transduced by brain cells into biochemical and genetic programs have received less attention. In this review, we described the composition of brain tissues and their pronounced microstructural heterogeneity. We discuss the individual role of neuronal and glial cell mechanics in brain homeostasis and diseases. We highlight how changes in the composition and mechanical properties of the extracellular matrix can modulate brain cell functions and describe key mechanisms of the mechanosensing process. We then consider the contribution of mechanobiology in the emergence of brain diseases by providing a critical review on traumatic brain injury, neurodegenerative diseases, and neuroblastoma. We show that a better understanding of the mechanobiology of brain tissues will require to manipulate the physico-chemical parameters of the cell microenvironment, and to develop three-dimensional models that can recapitulate the complexity and spatial diversity of brain tissues in a reproducible and predictable manner. Collectively, these emerging insights shed new light on the importance of mechanobiology and its implication in brain and nerve diseases.
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Affiliation(s)
- Anthony Procès
- Mechanobiology and Biomaterials group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, University of Mons, Mons, Belgium.,Neurosciences Department, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Marine Luciano
- Mechanobiology and Biomaterials group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Yohalie Kalukula
- Mechanobiology and Biomaterials group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Laurence Ris
- Neurosciences Department, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Sylvain Gabriele
- Mechanobiology and Biomaterials group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, University of Mons, Mons, Belgium
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Xolalpa-Cueva L, García-Carlos CA, Villaseñor-Zepeda R, Orta-Salazar E, Díaz-Cintra S, Peña-Ortega F, Perry G, Mondragón-Rodríguez S. Hyperphosphorylated Tau Relates to Improved Cognitive Performance and Reduced Hippocampal Excitability in the Young rTg4510 Mouse Model of Tauopathy. J Alzheimers Dis 2022; 87:529-543. [PMID: 35342085 DOI: 10.3233/jad-215186] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Tau hyperphosphorylation at several sites, including those close to its microtubule domain (MD), is considered a key pathogenic event in the development of tauopathies. Nevertheless, we recently demonstrated that at the very early disease stage, tau phosphorylation (pTau) at MD sites promotes neuroprotection by preventing seizure-like activity. OBJECTIVE To further support the notion that very early pTau is not detrimental, the present work evaluated the young rTg4510 mouse model of tauopathy as a case study. Thus, in mice at one month of age (PN30-35), we studied the increase of pTau within the hippocampal area as well as hippocampal and locomotor function. METHODS We used immunohistochemistry, T-maze, nesting test, novel object recognition test, open field arena, and electrophysiology. RESULTS Our results showed that the very young rTg4510 mouse model has no detectable changes in hippocampal dependent tasks, such as spontaneous alternation and nesting, or in locomotor activity. However, at this very early stage the hippocampal neurons from PN30-35 rTg4510 mice accumulate pTau protein and exhibit changes in hippocampal oscillatory activity. Moreover, we found a significant reduction in the somatic area of pTau positive pyramidal and granule neurons in the young rTg4510 mice. Despite this, improved memory and increased number of dendrites per cell in granule neurons was found. CONCLUSION Altogether, this study provides new insights into the early pathogenesis of tauopathies and provides further evidence that pTau remodels hippocampal function and morphology.
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Affiliation(s)
- Lorena Xolalpa-Cueva
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, Querétaro, México
| | - Carlos Antonio García-Carlos
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, Querétaro, México
| | - Rocío Villaseñor-Zepeda
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, Querétaro, México
| | - Erika Orta-Salazar
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, Querétaro, México
| | - Sofia Díaz-Cintra
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, Querétaro, México
| | - Fernando Peña-Ortega
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, Querétaro, México
| | - George Perry
- UTSA Neuroscience Institute and Department of Biology, College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Siddhartha Mondragón-Rodríguez
- UNAM Developmental Neurobiology and Neurophysiology, Institute of Neurobiology, National Autonomous University of México, Querétaro, México.,CONACYT National Council for Science and Technology, México, México
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Peña-Ortega F, Robles-Gómez ÁA, Xolalpa-Cueva L. Microtubules as Regulators of Neural Network Shape and Function: Focus on Excitability, Plasticity and Memory. Cells 2022; 11:cells11060923. [PMID: 35326374 PMCID: PMC8946818 DOI: 10.3390/cells11060923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 12/19/2022] Open
Abstract
Neuronal microtubules (MTs) are complex cytoskeletal protein arrays that undergo activity-dependent changes in their structure and function as a response to physiological demands throughout the lifespan of neurons. Many factors shape the allostatic dynamics of MTs and tubulin dimers in the cytosolic microenvironment, such as protein–protein interactions and activity-dependent shifts in these interactions that are responsible for their plastic capabilities. Recently, several findings have reinforced the role of MTs in behavioral and cognitive processes in normal and pathological conditions. In this review, we summarize the bidirectional relationships between MTs dynamics, neuronal processes, and brain and behavioral states. The outcomes of manipulating the dynamicity of MTs by genetic or pharmacological approaches on neuronal morphology, intrinsic and synaptic excitability, the state of the network, and behaviors are heterogeneous. We discuss the critical position of MTs as responders and adaptative elements of basic neuronal function whose impact on brain function is not fully understood, and we highlight the dilemma of artificially modulating MT dynamics for therapeutic purposes.
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Super-resolution microscopy: a closer look at synaptic dysfunction in Alzheimer disease. Nat Rev Neurosci 2021; 22:723-740. [PMID: 34725519 DOI: 10.1038/s41583-021-00531-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 11/08/2022]
Abstract
The synapse has emerged as a critical neuronal structure in the degenerative process of Alzheimer disease (AD), in which the pathogenic signals of two key players - amyloid-β (Aβ) and tau - converge, thereby causing synaptic dysfunction and cognitive deficits. The synapse presents a dynamic, confined microenvironment in which to explore how key molecules travel, localize, interact and assume different levels of organizational complexity, thereby affecting neuronal function. However, owing to their small size and the diffraction-limited resolution of conventional light microscopic approaches, investigating synaptic structure and dynamics has been challenging. Super-resolution microscopy (SRM) techniques have overcome the resolution barrier and are revolutionizing our quantitative understanding of biological systems in unprecedented spatio-temporal detail. Here we review critical new insights provided by SRM into the molecular architecture and dynamic organization of the synapse and, in particular, the interactions between Aβ and tau in this compartment. We further highlight how SRM can transform our understanding of the molecular pathological mechanisms that underlie AD. The application of SRM for understanding the roles of synapses in AD pathology will provide a stepping stone towards a broader understanding of dysfunction in other subcellular compartments and at cellular and circuit levels in this disease.
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Chang CW, Evans MD, Yu X, Yu GQ, Mucke L. Tau reduction affects excitatory and inhibitory neurons differently, reduces excitation/inhibition ratios, and counteracts network hypersynchrony. Cell Rep 2021; 37:109855. [PMID: 34686344 PMCID: PMC8648275 DOI: 10.1016/j.celrep.2021.109855] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/04/2021] [Accepted: 09/27/2021] [Indexed: 11/27/2022] Open
Abstract
The protein tau has been implicated in many brain disorders. In animal models, tau reduction suppresses epileptogenesis of diverse causes and ameliorates synaptic and behavioral abnormalities in various conditions associated with excessive excitation-inhibition (E/I) ratios. However, the underlying mechanisms are unknown. Global genetic ablation of tau in mice reduces the action potential (AP) firing and E/I ratio of pyramidal cells in acute cortical slices without affecting the excitability of these cells. Tau ablation reduces the excitatory inputs to inhibitory neurons, increases the excitability of these cells, and structurally alters their axon initial segments (AISs). In primary neuronal cultures subjected to prolonged overstimulation, tau ablation diminishes the homeostatic response of AISs in inhibitory neurons, promotes inhibition, and suppresses hypersynchrony. Together, these differential alterations in excitatory and inhibitory neurons help explain how tau reduction prevents network hypersynchrony and counteracts brain disorders causing abnormally increased E/I ratios.
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Affiliation(s)
- Che-Wei Chang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Mark D Evans
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Xinxing Yu
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, CA 94158, USA; Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, CA 94158, USA.
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