1
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Russo ML, Ayala G, Neal D, Rogalsky AE, Ahmad S, Musial TF, Pearlman M, Bean LA, Farooqi AK, Ahmed A, Castaneda A, Patel A, Parduhn Z, Haddad LG, Gabriel A, Disterhoft JF, Nicholson DA. Alzheimer's-linked axonal changes accompany elevated antidromic action potential failure rate in aged mice. Brain Res 2024; 1841:149083. [PMID: 38866308 PMCID: PMC11323114 DOI: 10.1016/j.brainres.2024.149083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/22/2024] [Accepted: 06/09/2024] [Indexed: 06/14/2024]
Abstract
Alzheimer's disease (AD) affects both grey and white matter (WM), but considerably more is known about the former. Interestingly, WM disruption has been consistently observed and thoroughly described using imaging modalities, particularly MRI which has shown WM functional disconnections between the hippocampus and other brain regions during AD pathogenesis when early neurodegeneration and synapse loss are also evident. Nonetheless, high-resolution structural and functional analyses of WM during AD pathogenesis remain scarce. Given the importance of the myelinated axons in the WM for conveying information across brain regions, such studies will provide valuable information on the cellular drivers and consequences of WM disruption that contribute to the characteristic cognitive decline of AD. Here, we employed a multi-scale approach to investigate hippocampal WM disruption during AD pathogenesis and determine whether hippocampal WM changes accompany the well-documented grey matter losses. Our data indicate that ultrastructural myelin disruption is elevated in the alveus in human AD cases and increases with age in 5xFAD mice. Unreliable action potential propagation and changes to sodium channel expression at the node of Ranvier co-emerged with this deterioration. These findings provide important insight to the neurobiological substrates and functional consequences of decreased WM integrity and are consistent with the notion that hippocampal disconnection contributes to cognitive changes in AD.
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Affiliation(s)
- Matthew L Russo
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA.
| | - Gelique Ayala
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Demetria Neal
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Annalise E Rogalsky
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Suzan Ahmad
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Timothy F Musial
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Morgan Pearlman
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Linda A Bean
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Anise K Farooqi
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Aysha Ahmed
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Adrian Castaneda
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Aneri Patel
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Zachary Parduhn
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Loreece G Haddad
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Ashley Gabriel
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - John F Disterhoft
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Daniel A Nicholson
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
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2
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Bagheri H, Friedman H, Hadwen A, Jarweh C, Cooper E, Oprea L, Guerrier C, Khadra A, Collin A, Cohen-Adad J, Young A, Victoriano GM, Swire M, Jarjour A, Bechler ME, Pryce RS, Chaurand P, Cougnaud L, Vuckovic D, Wilion E, Greene O, Nishiyama A, Benmamar-Badel A, Owens T, Grouza V, Tuznik M, Liu H, Rudko DA, Zhang J, Siminovitch KA, Peterson AC. Myelin basic protein mRNA levels affect myelin sheath dimensions, architecture, plasticity, and density of resident glial cells. Glia 2024; 72:1893-1914. [PMID: 39023138 DOI: 10.1002/glia.24589] [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: 08/07/2024] [Revised: 05/29/2024] [Accepted: 06/23/2024] [Indexed: 07/20/2024]
Abstract
Myelin Basic Protein (MBP) is essential for both elaboration and maintenance of CNS myelin, and its reduced accumulation results in hypomyelination. How different Mbp mRNA levels affect myelin dimensions across the lifespan and how resident glial cells may respond to such changes are unknown. Here, to investigate these questions, we used enhancer-edited mouse lines that accumulate Mbp mRNA levels ranging from 8% to 160% of wild type. In young mice, reduced Mbp mRNA levels resulted in corresponding decreases in Mbp protein accumulation and myelin sheath thickness, confirming the previously demonstrated rate-limiting role of Mbp transcription in the control of initial myelin synthesis. However, despite maintaining lower line specific Mbp mRNA levels into old age, both MBP protein levels and myelin thickness improved or fully normalized at rates defined by the relative Mbp mRNA level. Sheath length, in contrast, was affected only when mRNA levels were very low, demonstrating that sheath thickness and length are not equally coupled to Mbp mRNA level. Striking abnormalities in sheath structure also emerged with reduced mRNA levels. Unexpectedly, an increase in the density of all glial cell types arose in response to reduced Mbp mRNA levels. This investigation extends understanding of the role MBP plays in myelin sheath elaboration, architecture, and plasticity across the mouse lifespan and illuminates a novel axis of glial cell crosstalk.
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Affiliation(s)
- Hooman Bagheri
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Hana Friedman
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Amanda Hadwen
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Celia Jarweh
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Ellis Cooper
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Lawrence Oprea
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | | | - Anmar Khadra
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | - Armand Collin
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada
| | - Julien Cohen-Adad
- Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada
| | - Amanda Young
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Gerardo Mendez Victoriano
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Matthew Swire
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Andrew Jarjour
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Marie E Bechler
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Rachel S Pryce
- Department of Chemistry, Université de Montréal, Montreal, Quebec, Canada
| | - Pierre Chaurand
- Department of Chemistry, Université de Montréal, Montreal, Quebec, Canada
| | - Lise Cougnaud
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Dajana Vuckovic
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Elliott Wilion
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Owen Greene
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Akiko Nishiyama
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, USA
- The Connecticut Institute for Brain and Cognitive Sciences, University of Connecticut, Storrs, Connecticut, USA
| | - Anouk Benmamar-Badel
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Trevor Owens
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Vladimir Grouza
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Marius Tuznik
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Hanwen Liu
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - David A Rudko
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Jinyi Zhang
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital, Lunenfeld-Tanenbaum and Toronto General Hospital Research Institutes, Toronto, Ontario, Canada
| | - Katherine A Siminovitch
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital, Lunenfeld-Tanenbaum and Toronto General Hospital Research Institutes, Toronto, Ontario, Canada
| | - Alan C Peterson
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Gerald Bronfman Department of Oncology, McGill University, Quebec, Canada
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3
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Huang WQ, Sheng H, Wang H, Qi Y, Wang F, Hua Y. Volume electron microscopy reveals age-related ultrastructural differences of globular bush cell axons in mouse central auditory system. Neurobiol Aging 2024; 136:111-124. [PMID: 38342072 DOI: 10.1016/j.neurobiolaging.2024.01.016] [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: 07/27/2022] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/13/2024]
Abstract
In mammals, thick axonal calibers wrapped with heavy myelin sheaths are prevalent in the auditory nervous system. These features are crucial for fast traveling of nerve impulses with minimal attenuation required for sound signal transmission. In particular, the long-range projections from the cochlear nucleus - the axons of globular bush cells (GBCs) - to the medial nucleus of the trapezoid body (MNTB) are tonotopically organized. However, it remains controversial in gerbils and mice whether structural and functional adaptations are present among the GBC axons targeting different MNTB frequency regions. By means of high-throughput volume electron microscopy, we compared the GBC axons in full-tonotopy-ranged MNTB slices from the C57BL/6 mice at different ages. Our quantification reveals distinct caliber diameter and myelin profile of the GBC axons with endings at lateral and medial MNTB, arguing for modulation of functionally heterogeneous axon subgroups. In addition, we reported axon-specific differences in axon caliber, node of Ranvier, and myelin sheath among juvenile, adult, and old mice, indicating the age-related changes of GBC axon morphology over time. These findings provide structural insight into the maturation and degeneration of GBC axons with frequency tuning across the lifespan of mice.
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Affiliation(s)
- Wen-Qing Huang
- Department of Otolaryngology-Head and Neck Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China; Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Central Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Haibin Sheng
- Department of Otolaryngology-Head and Neck Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Haoyu Wang
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yumeng Qi
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fangfang Wang
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Yunfeng Hua
- Department of Otolaryngology-Head and Neck Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China; Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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4
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Moore TL, Medalla M, Ibañez S, Wimmer K, Mojica CA, Killiany RJ, Moss MB, Luebke JI, Rosene DL. Neuronal properties of pyramidal cells in lateral prefrontal cortex of the aging rhesus monkey brain are associated with performance deficits on spatial working memory but not executive function. GeroScience 2023:10.1007/s11357-023-00798-2. [PMID: 37106282 PMCID: PMC10400510 DOI: 10.1007/s11357-023-00798-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
Age-related declines in cognitive abilities occur as early as middle-age in humans and rhesus monkeys. Specifically, performance by aged individuals on tasks of executive function (EF) and working memory (WM) is characterized by greater frequency of errors, shorter memory spans, increased frequency of perseverative responses, impaired use of feedback and reduced speed of processing. However, how aging precisely differentially impacts specific aspects of these cognitive functions and the distinct brain areas mediating cognition are not well understood. The prefrontal cortex (PFC) is known to mediate EF and WM and is an area that shows a vulnerability to age-related alterations in neuronal morphology. In the current study, we show that performance on EF and WM tasks exhibited significant changes with age, and these impairments correlate with changes in biophysical properties of layer 3 (L3) pyramidal neurons in lateral LPFC (LPFC). Specifically, there was a significant age-related increase in excitability of L3 LPFC pyramidal neurons, consistent with previous studies. Further, this age-related hyperexcitability of LPFC neurons was significantly correlated with age-related decline on a task of WM, but not an EF task. The current study characterizes age-related performance on tasks of WM and EF and provides insight into the neural substrates that may underlie changes in both WM and EF with age.
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Affiliation(s)
- Tara L Moore
- Department of Anatomy & Neurobiology, Boston University Chobanian & Avedisian School of Medicine, 700 Albany Street, W701, MA, 02118, Boston, USA.
- Center for Systems Neuroscience, Boston University, MA, 02115, Boston, USA.
| | - Maria Medalla
- Department of Anatomy & Neurobiology, Boston University Chobanian & Avedisian School of Medicine, 700 Albany Street, W701, MA, 02118, Boston, USA
- Center for Systems Neuroscience, Boston University, MA, 02115, Boston, USA
| | - Sara Ibañez
- Centre de Recerca Matemàtica, Edifici C, Campus Bellaterra, 08193, Bellaterra, Spain
| | - Klaus Wimmer
- Centre de Recerca Matemàtica, Edifici C, Campus Bellaterra, 08193, Bellaterra, Spain
| | - Chromewell A Mojica
- Department of Anatomy & Neurobiology, Boston University Chobanian & Avedisian School of Medicine, 700 Albany Street, W701, MA, 02118, Boston, USA
| | - Ronald J Killiany
- Department of Anatomy & Neurobiology, Boston University Chobanian & Avedisian School of Medicine, 700 Albany Street, W701, MA, 02118, Boston, USA
- Center for Systems Neuroscience, Boston University, MA, 02115, Boston, USA
| | - Mark B Moss
- Department of Anatomy & Neurobiology, Boston University Chobanian & Avedisian School of Medicine, 700 Albany Street, W701, MA, 02118, Boston, USA
- Center for Systems Neuroscience, Boston University, MA, 02115, Boston, USA
| | - Jennifer I Luebke
- Department of Anatomy & Neurobiology, Boston University Chobanian & Avedisian School of Medicine, 700 Albany Street, W701, MA, 02118, Boston, USA
- Center for Systems Neuroscience, Boston University, MA, 02115, Boston, USA
| | - Douglas L Rosene
- Department of Anatomy & Neurobiology, Boston University Chobanian & Avedisian School of Medicine, 700 Albany Street, W701, MA, 02118, Boston, USA
- Center for Systems Neuroscience, Boston University, MA, 02115, Boston, USA
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5
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Alesci A, Pergolizzi S, Mokhtar DM, Fumia A, Aragona M, Lombardo GP, Messina E, D'Angelo R, Lo Cascio P, Sayed RKA, Albano M, Capillo G, Lauriano ER. Morpho-structural adaptations of the integument in different aquatic organisms. Acta Histochem 2023; 125:152031. [PMID: 37075648 DOI: 10.1016/j.acthis.2023.152031] [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: 02/28/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 04/21/2023]
Abstract
The integument acts as a barrier to protect the body from harmful pathogenic infectious agents, parasites, UV rays, trauma, and germs. The integument of invertebrates and vertebrates are structurally different: while invertebrates usually have a simple monolayer epidermis frequently covered by mucus, cuticles, or mineralized structures, vertebrates possess a multilayered epidermis with several specialized cells. This study aims to describe by morphological, histological, and immunohistochemical analyses, the morpho-structural adaptations throughout evolution of the integument of gastropod Aplysia depilans (Gmelin, 1791), ascidian Styela plicata (Lesuer, 1823), myxine hagfish Eptatretus cirrhatus (Forster, 1801) and teleost Heteropneustes fossilis (Bloch, 1794) for the first time, with special reference to sensory epidermal cells. Different types of cells could be identified that varied according to the species; including mucous cells, serous glandular cells, clavate cells, club cells, thread cells, and support cells. In all integuments of the specimens analyzed, sensory solitary cells were identified in the epidermis, immunoreactive to serotonin and calbindin. Our study provided an essential comparison of integuments, adding new information about sensory epidermal cells phylogenetic conservation and on the structural changes that invertebrates and vertebrates have undergone during evolution.
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Affiliation(s)
- Alessio Alesci
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, 98166 Messina, Italy.
| | - Simona Pergolizzi
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Doaa M Mokhtar
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Assiut University, Assiut 71526, Egypt
| | - Angelo Fumia
- Department of Clinical and Experimental Medicine, University of Messina, Padiglione C, A. O. U. Policlinico "G. Martino", 98124 Messina, Italy.
| | - Marialuisa Aragona
- Department of Veterinary Sciences, University of Messina, 98168 Messina, Italy
| | - Giorgia Pia Lombardo
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Emmanuele Messina
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Roberta D'Angelo
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Patrizia Lo Cascio
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Ramy K A Sayed
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Sohag University, Sohag 82524, Egypt
| | - Marco Albano
- Department of Veterinary Sciences, University of Messina, 98168 Messina, Italy
| | - Gioele Capillo
- Department of Veterinary Sciences, University of Messina, 98168 Messina, Italy; Institute for Marine Biological Resources and Biotechnology (IRBIM), National Research Council (CNR), Section of Messina, 98100 Messina, Italy
| | - Eugenia Rita Lauriano
- Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, 98166 Messina, Italy
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6
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The times they are a-changin': a proposal on how brain flexibility goes beyond the obvious to include the concepts of "upward" and "downward" to neuroplasticity. Mol Psychiatry 2023; 28:977-992. [PMID: 36575306 PMCID: PMC10005965 DOI: 10.1038/s41380-022-01931-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/07/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022]
Abstract
Since the brain was found to be somehow flexible, plastic, researchers worldwide have been trying to comprehend its fundamentals to better understand the brain itself, make predictions, disentangle the neurobiology of brain diseases, and finally propose up-to-date treatments. Neuroplasticity is simple as a concept, but extremely complex when it comes to its mechanisms. This review aims to bring to light an aspect about neuroplasticity that is often not given enough attention as it should, the fact that the brain's ability to change would include its ability to disconnect synapses. So, neuronal shrinkage, decrease in spine density or dendritic complexity should be included within the concept of neuroplasticity as part of its mechanisms, not as an impairment of it. To that end, we extensively describe a variety of studies involving topics such as neurodevelopment, aging, stress, memory and homeostatic plasticity to highlight how the weakening and disconnection of synapses organically permeate the brain in so many ways as a good practice of its intrinsic physiology. Therefore, we propose to break down neuroplasticity into two sub-concepts, "upward neuroplasticity" for changes related to synaptic construction and "downward neuroplasticity" for changes related to synaptic deconstruction. With these sub-concepts, neuroplasticity could be better understood from a bigger landscape as a vector in which both directions could be taken for the brain to flexibly adapt to certain demands. Such a paradigm shift would allow a better understanding of the concept of neuroplasticity to avoid any data interpretation bias, once it makes clear that there is no morality with regard to the organic and physiological changes that involve dynamic biological systems as seen in the brain.
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7
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Moore TL, Medalla M, Iba Ez S, Wimmer K, Mojica CA, Killiany RJ, Moss MB, Luebke JI, Rosene DL. Neuronal properties of pyramidal cells in lateral prefrontal cortex of the aging rhesus monkey brain are associated with performance deficits on spatial working memory but not executive function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.07.527321. [PMID: 36798388 PMCID: PMC9934587 DOI: 10.1101/2023.02.07.527321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Age-related declines in cognitive abilities occur as early as middle-age in humans and rhesus monkeys. Specifically, performance by aged individuals on tasks of executive function (EF) and working memory (WM) is characterized by greater frequency of errors, shorter memory spans, increased frequency of perseverative responses, impaired use of feedback and reduced speed of processing. However, how aging precisely differentially impacts specific aspects of these cognitive functions and the distinct brain areas mediating cognition are not well understood. The prefrontal cortex (PFC) is known to mediate EF and WM and is an area that shows a vulnerability to age-related alterations in neuronal morphology. In the current study, we show that performance on EF and WM tasks exhibited significant changes with age and these impairments correlate with changes in biophysical properties of L3 pyramidal neurons in lateral LPFC (LPFC). Specifically, there was a significant age-related increase in excitability of Layer 3 LPFC pyramidal neurons, consistent with previous studies. Further, this age-related hyperexcitability of LPFC neurons was significantly correlated with age-related decline on a task of WM, but not an EF task. The current study characterizes age-related performance on tasks of WM and EF and provides insight into the neural substrates that may underlie changes in both WM and EF with age.
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8
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McNamara NB, Munro DAD, Bestard-Cuche N, Uyeda A, Bogie JFJ, Hoffmann A, Holloway RK, Molina-Gonzalez I, Askew KE, Mitchell S, Mungall W, Dodds M, Dittmayer C, Moss J, Rose J, Szymkowiak S, Amann L, McColl BW, Prinz M, Spires-Jones TL, Stenzel W, Horsburgh K, Hendriks JJA, Pridans C, Muramatsu R, Williams A, Priller J, Miron VE. Microglia regulate central nervous system myelin growth and integrity. Nature 2023; 613:120-129. [PMID: 36517604 PMCID: PMC9812791 DOI: 10.1038/s41586-022-05534-y] [Citation(s) in RCA: 99] [Impact Index Per Article: 99.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 11/05/2022] [Indexed: 12/15/2022]
Abstract
Myelin is required for the function of neuronal axons in the central nervous system, but the mechanisms that support myelin health are unclear. Although macrophages in the central nervous system have been implicated in myelin health1, it is unknown which macrophage populations are involved and which aspects they influence. Here we show that resident microglia are crucial for the maintenance of myelin health in adulthood in both mice and humans. We demonstrate that microglia are dispensable for developmental myelin ensheathment. However, they are required for subsequent regulation of myelin growth and associated cognitive function, and for preservation of myelin integrity by preventing its degeneration. We show that loss of myelin health due to the absence of microglia is associated with the appearance of a myelinating oligodendrocyte state with altered lipid metabolism. Moreover, this mechanism is regulated through disruption of the TGFβ1-TGFβR1 axis. Our findings highlight microglia as promising therapeutic targets for conditions in which myelin growth and integrity are dysregulated, such as in ageing and neurodegenerative disease2,3.
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Affiliation(s)
- Niamh B McNamara
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
- Medical Research Council Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
| | - David A D Munro
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Nadine Bestard-Cuche
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK
| | - Akiko Uyeda
- Departments of Molecular Pharmacology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Jeroen F J Bogie
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Hasselt, Belgium
- University MS Centre, Hasselt University, Hasselt, Belgium
| | - Alana Hoffmann
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
- Medical Research Council Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Rebecca K Holloway
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
- Medical Research Council Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
- Barlo Multiple Sclerosis Centre, St Michael's Hospital, Toronto, Ontario, Canada
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Toronto, Ontario, Canada
- Department of Immunology, The University of Toronto, Toronto, Ontario, Canada
| | - Irene Molina-Gonzalez
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
- Medical Research Council Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Katharine E Askew
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Stephen Mitchell
- Wellcome Trust Centre for Cell Biology, King's Buildings, The University of Edinburgh, Edinburgh, UK
| | - William Mungall
- Biological and Veterinary Services, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Michael Dodds
- Biological and Veterinary Services, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Carsten Dittmayer
- Department of Neuropathology and Neurocure Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jonathan Moss
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK
| | - Jamie Rose
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Stefan Szymkowiak
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Lukas Amann
- Institute of Neuropathology, Centre for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Barry W McColl
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Marco Prinz
- Institute of Neuropathology, Centre for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Tara L Spires-Jones
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Werner Stenzel
- Department of Neuropathology and Neurocure Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Karen Horsburgh
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Jerome J A Hendriks
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Hasselt, Belgium
- University MS Centre, Hasselt University, Hasselt, Belgium
| | - Clare Pridans
- Centre for Inflammation Research, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK
| | - Rieko Muramatsu
- Departments of Molecular Pharmacology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Anna Williams
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh, UK
| | - Josef Priller
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
- Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
- Neuropsychiatry and Laboratory of Molecular Psychiatry, Charité-Universitätsmedizin Berlin and DZNE, Berlin, Germany
| | - Veronique E Miron
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK.
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK.
- Medical Research Council Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, UK.
- Barlo Multiple Sclerosis Centre, St Michael's Hospital, Toronto, Ontario, Canada.
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Toronto, Ontario, Canada.
- Department of Immunology, The University of Toronto, Toronto, Ontario, Canada.
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9
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Clark IA, Mohammadi S, Callaghan MF, Maguire EA. Conduction velocity along a key white matter tract is associated with autobiographical memory recall ability. eLife 2022; 11:79303. [PMID: 36166372 PMCID: PMC9514844 DOI: 10.7554/elife.79303] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 09/12/2022] [Indexed: 12/01/2022] Open
Abstract
Conduction velocity is the speed at which electrical signals travel along axons and is a crucial determinant of neural communication. Inferences about conduction velocity can now be made in vivo in humans using a measure called the magnetic resonance (MR) g-ratio. This is the ratio of the inner axon diameter relative to that of the axon plus the myelin sheath that encases it. Here, in the first application to cognition, we found that variations in MR g-ratio, and by inference conduction velocity, of the parahippocampal cingulum bundle were associated with autobiographical memory recall ability in 217 healthy adults. This tract connects the hippocampus with a range of other brain areas. We further observed that the association seemed to be with inner axon diameter rather than myelin content. The extent to which neurites were coherently organised within the parahippocampal cingulum bundle was also linked with autobiographical memory recall ability. Moreover, these findings were specific to autobiographical memory recall and were not apparent for laboratory-based memory tests. Our results offer a new perspective on individual differences in autobiographical memory recall ability, highlighting the possible influence of specific white matter microstructure features on conduction velocity when recalling detailed memories of real-life past experiences.
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Affiliation(s)
- Ian A Clark
- Wellcome Centre for Human Neuroimaging, Department of Imaging Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Siawoosh Mohammadi
- Institute of Systems Neuroscience, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Martina F Callaghan
- Wellcome Centre for Human Neuroimaging, Department of Imaging Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Eleanor A Maguire
- Wellcome Centre for Human Neuroimaging, Department of Imaging Neuroscience, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
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10
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Aires V, Ziegler-Waldkirch S, Friesen M, Reichardt W, Erny D, Loreth D, Harborne A, Kretz O, von Elverfeldt D, Meyer-Luehmann M. Seed-induced Aβ deposits in the corpus callosum disrupt white matter integrity in a mouse model of Alzheimer’s disease. Front Cell Neurosci 2022; 16:862918. [PMID: 36003141 PMCID: PMC9393256 DOI: 10.3389/fncel.2022.862918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Neuropathologically, Alzheimer’s disease (AD) is characterized by the accumulation of amyloid-beta peptide (Aβ) and subsequent formation of the so-called Aβ plaques. Along with neuronal loss, previous studies report white matter anomalies and corpus callosum (CC) atrophy in AD patients. Notably, perturbations in the white matter can be observed years before expected disease onset, suggesting that early stages of disease progression play a role in AD-associated loss of myelin integrity. Through seed-induced deposition of Aβ, we are able to examine alterations of central nervous system (CNS) integrity during the initial stages of plaque formation. In this study, we investigate the impact of Aβ seeding in the CC utilizing various imaging techniques as well as quantitative gene expression analysis and demonstrate that Aβ deposits result in an imbalance of glial cells in the CC. We found increased amounts of phagocytic microglia and reactive astrocytes, while oligodendrocyte progenitor cell (OPC) numbers were reduced. Moreover, white matter aberrations adjacent to the Aβ seeding were observed together with an overall decline in callosal myelination. This data indicate that the initial stages of plaque formation induce oligodendrocyte dysfunction, which might ultimately lead to myelin loss.
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Affiliation(s)
- Vanessa Aires
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Stephanie Ziegler-Waldkirch
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marina Friesen
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Wilfried Reichardt
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Medical Physics, Medical Center – University of Freiburg, Freiburg, Germany
- German Consortium for Translational Cancer Research (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniel Erny
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute of Neuropathology, University of Freiburg, Freiburg, Germany
- Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Desiree Loreth
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andrew Harborne
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Oliver Kretz
- Department of Internal Medicine III, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Dominik von Elverfeldt
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Medical Physics, Medical Center – University of Freiburg, Freiburg, Germany
| | - Melanie Meyer-Luehmann
- Department of Neurology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- *Correspondence: Melanie Meyer-Luehmann,
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11
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The ultrastructural study of human cochlear nerve at different ages. Hear Res 2022; 416:108443. [DOI: 10.1016/j.heares.2022.108443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/11/2022] [Accepted: 01/16/2022] [Indexed: 11/21/2022]
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12
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Scott JT, Bourne JA. Modelling behaviors relevant to brain disorders in the nonhuman primate: Are we there yet? Prog Neurobiol 2021; 208:102183. [PMID: 34728308 DOI: 10.1016/j.pneurobio.2021.102183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 12/30/2022]
Abstract
Recent years have seen a profound resurgence of activity with nonhuman primates (NHPs) to model human brain disorders. From marmosets to macaques, the study of NHP species offers a unique window into the function of primate-specific neural circuits that are impossible to examine in other models. Examining how these circuits manifest into the complex behaviors of primates, such as advanced cognitive and social functions, has provided enormous insights to date into the mechanisms underlying symptoms of numerous neurological and neuropsychiatric illnesses. With the recent optimization of modern techniques to manipulate and measure neural activity in vivo, such as optogenetics and calcium imaging, NHP research is more well-equipped than ever to probe the neural mechanisms underlying pathological behavior. However, methods for behavioral experimentation and analysis in NHPs have noticeably failed to keep pace with these advances. As behavior ultimately lies at the junction between preclinical findings and its translation to clinical outcomes for brain disorders, approaches to improve the integrity, reproducibility, and translatability of behavioral experiments in NHPs requires critical evaluation. In this review, we provide a unifying account of existing brain disorder models using NHPs, and provide insights into the present and emerging contributions of behavioral studies to the field.
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Affiliation(s)
- Jack T Scott
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - James A Bourne
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia.
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13
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Comparative Review of Microglia and Monocytes in CNS Phagocytosis. Cells 2021; 10:cells10102555. [PMID: 34685535 PMCID: PMC8534258 DOI: 10.3390/cells10102555] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 01/08/2023] Open
Abstract
Macrophages maintain tissue homeostasis by phagocytosing and removing unwanted materials such as dead cells and cell debris. Microglia, the resident macrophages of the central nervous system (CNS), are no exception. In addition, a series of recent studies have shown that microglia phagocytose the neuronal synapses that form the basis of neural circuit function. This discovery has spurred many neuroscientists to study microglia. Importantly, in the CNS parenchyma, not only microglia but also blood-derived monocytes, which essentially differentiate into macrophages after infiltration, exert phagocytic ability, making the study of phagocytosis in the CNS even more interesting and complex. In particular, in the diseased brain, the phagocytosis of tissue-damaging substances, such as myelin debris in multiple sclerosis (MS), has been shown to be carried out by both microglia and blood-derived monocytes. However, it remains largely unclear why blood-derived monocytes need to invade the parenchyma, where microglia are already abundant, to assist in phagocytosis. We will also discuss whether this phagocytosis can affect the fate of the phagocytosing cell itself as well as the substance being phagocytosed and the surrounding environment in addition to future research directions. In this review, we will introduce recent studies to answer a question that often arises when studying microglial phagocytosis: under what circumstances and to what extent blood-derived monocytes infiltrate the CNS and contribute to phagocytosis. In addition, the readers will learn how recent studies have experimentally distinguished between microglia and infiltrating monocytes. Finally, we aim to contribute to the progress of phagocytosis research by discussing the effects of phagocytosis on phagocytic cells.
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14
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Pannese E. Quantitative, structural and molecular changes in neuroglia of aging mammals: A review. Eur J Histochem 2021; 65. [PMID: 34346664 PMCID: PMC8239453 DOI: 10.4081/ejh.2021.3249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 05/27/2021] [Indexed: 01/06/2023] Open
Abstract
The neuroglia of the central and peripheral nervous systems undergo numerous changes during normal aging. Astrocytes become hypertrophic and accumulate intermediate filaments. Oligodendrocytes and Schwann cells undergo alterations that are often accompanied by degenerative changes to the myelin sheath. In microglia, proliferation in response to injury, motility of cell processes, ability to migrate to sites of neural injury, and phagocytic and autophagic capabilities are reduced. In sensory ganglia, the number and extent of gaps between perineuronal satellite cells – that leave the surfaces of sensory ganglion neurons directly exposed to basal lamina – increase significantly. The molecular profiles of neuroglia also change in old age, which, in view of the interactions between neurons and neuroglia, have negative consequences for important physiological processes in the nervous system. Since neuroglia actively participate in numerous nervous system processes, it is likely that not only neurons but also neuroglia will prove to be useful targets for interventions to prevent, reverse or slow the behavioral changes and cognitive decline that often accompany senescence.
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Affiliation(s)
- Ennio Pannese
- Emeritus, Full Professor of Normal Human Anatomy and Neurocytology at the University of Milan.
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15
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Differential Circuit Mechanisms of Young and Aged Visual Cortex in the Mammalian Brain. NEUROSCI 2021. [DOI: 10.3390/neurosci2010001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The main goal of this review is to summarize and discuss (1) age-dependent structural reorganization of mammalian visual cortical circuits underlying complex visual behavior functions in primary visual cortex (V1) and multiple extrastriate visual areas, and (2) current evidence supporting the notion of compensatory mechanisms in aged visual circuits as well as the use of rehabilitative therapy for the recovery of neural plasticity in normal and diseased aging visual circuit mechanisms in different species. It is well known that aging significantly modulates both the structural and physiological properties of visual cortical neurons in V1 and other visual cortical areas in various species. Compensatory aged neural mechanisms correlate with the complexity of visual functions; however, they do not always result in major circuit alterations resulting in age-dependent decline in performance of a visual task or neurodegenerative disorders. Computational load and neural processing gradually increase with age, and the complexity of compensatory mechanisms correlates with the intricacy of higher form visual perceptions that are more evident in higher-order visual areas. It is particularly interesting to note that the visual perceptual processing of certain visual behavior functions does not change with age. This review aims to comprehensively discuss the effect of normal aging on neuroanatomical alterations that underlie critical visual functions and more importantly to highlight differences between compensatory mechanisms in aged neural circuits and neural processes related to visual disorders. This type of approach will further enhance our understanding of inter-areal and cortico-cortical connectivity of visual circuits in normal aging and identify major circuit alterations that occur in different visual deficits, thus facilitating the design and evaluation of potential rehabilitation therapies as well as the assessment of the extent of their rejuvenation.
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16
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Panta A, Montgomery K, Nicolas M, Mani KK, Sampath D, Sohrabji F. Mir363-3p Treatment Attenuates Long-Term Cognitive Deficits Precipitated by an Ischemic Stroke in Middle-Aged Female Rats. Front Aging Neurosci 2020; 12:586362. [PMID: 33132904 PMCID: PMC7550720 DOI: 10.3389/fnagi.2020.586362] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/02/2020] [Indexed: 01/29/2023] Open
Abstract
Cognitive impairment and memory loss are commonly seen after stroke and a third of patients will develop signs of dementia a year after stroke. Despite a large number of studies on the beneficial effects of neuroprotectants, few studies have examined the effects of these compounds/interventions on long-term cognitive impairment. Our previous work showed that the microRNA mir363-3p reduced infarct volume and sensory-motor impairment in the acute stage of stroke in middle-aged females but not males. Thus, the present study determined the impact of mir363-3p treatment on stroke-induced cognitive impairment in middle-aged females. Sprague–Dawley female rats (12 months of age) were subjected to middle cerebral artery occlusion (MCAo; or sham surgery) and injected (iv) with mir363-3p mimic (MCAo + mir363-3p) or scrambled oligos (MCAo + scrambled) 4 h later. Sensory-motor performance was assessed in the acute phase (2–5 days after stroke), while all other behaviors were tested 6 months after MCAo (18 months of age). Cognitive function was assessed by the novel object recognition test (declarative memory) and the Barnes maze (spatial memory). The MCAo + scrambled group showed reduced preference for a novel object after the stroke and poor learning in the spatial memory task. In contrast, mir363-3p treated animals were similar to either their baseline performance or to the sham group. Histological analysis showed significant deterioration of specific white matter tracts due to stroke, which was attenuated in mir363-3p treated animals. The present data builds on our previous finding to show that a neuroprotectant can abrogate the long-term effects of stroke.
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Affiliation(s)
- Aditya Panta
- Women's Health in Neuroscience Program, Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center College of Medicine, Texas A&M University, Bryan, TX, United States
| | - Karienn Montgomery
- Women's Health in Neuroscience Program, Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center College of Medicine, Texas A&M University, Bryan, TX, United States
| | - Marissa Nicolas
- Women's Health in Neuroscience Program, Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center College of Medicine, Texas A&M University, Bryan, TX, United States
| | - Kathiresh K Mani
- Women's Health in Neuroscience Program, Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center College of Medicine, Texas A&M University, Bryan, TX, United States
| | - Dayalan Sampath
- Women's Health in Neuroscience Program, Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center College of Medicine, Texas A&M University, Bryan, TX, United States
| | - Farida Sohrabji
- Women's Health in Neuroscience Program, Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center College of Medicine, Texas A&M University, Bryan, TX, United States
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17
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Salas IH, Burgado J, Allen NJ. Glia: victims or villains of the aging brain? Neurobiol Dis 2020; 143:105008. [PMID: 32622920 DOI: 10.1016/j.nbd.2020.105008] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 06/14/2020] [Accepted: 06/29/2020] [Indexed: 12/11/2022] Open
Abstract
Aging is the strongest risk factor for metabolic, vascular and neurodegenerative diseases. Aging alone is associated with a gradual decline of cognitive and motor functions. Considering an increasing elderly population in the last century, understanding the cellular and molecular mechanisms contributing to brain aging is of vital importance. Recent genetic and transcriptomic findings strongly suggest that glia are the first cells changing with aging. Glial cells constitute around 50% of the total cells in the brain and play key roles regulating brain homeostasis in health and disease. Their essential functions include providing nutritional support to neurons, activation of immune responses, and regulation of synaptic transmission and plasticity. In this review we discuss how glia are altered in the aging brain and whether these alterations are protective or contribute to the age-related pathological cascade. We focus on the major morphological, transcriptional and functional changes affecting glia in a range of systems, including human, non-human primates, and rodents. We also highlight future directions for investigating the roles of glia in brain aging.
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Affiliation(s)
- Isabel H Salas
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jillybeth Burgado
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Nicola J Allen
- Salk Institute for Biological Studies, Molecular Neurobiology Laboratory, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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18
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Qi X, Fan H, Yang X, Chen Y, Deng W, Guo W, Wang Q, Chen E, Li T, Ma X. High level of pattern glare in major depressive disorder. BMC Psychiatry 2019; 19:415. [PMID: 31864335 PMCID: PMC6925875 DOI: 10.1186/s12888-019-2399-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 12/09/2019] [Indexed: 02/09/2023] Open
Abstract
BACKGROUND Visual deficits have been reported in abundance by recent studies on major depressive disorder. Pattern glare manifests as visual distortions, such as the symptoms of headache, glare, eyestrain, illusions of shapes, colors, and motion when viewing repetitive striped patterns, of which some can be observed in major depressive disorder. Inspired by what mentioned, the present study aims to explore whether there exists association between pattern glare and major depressive disorder and further attempts to explore possible clinical diagnostic value of pattern glare in major depressive disorder. METHODS Twenty-four patients diagnosed with major depressive disorder (MDDs group) were compared with 30 age-, gender- and education level-matched healthy control subjects (HCs group) on their visual stress with black-and-white gratings of different spatial frequencies-0.3 (low-SF), 2.3 (mid-SF), and 9.4 (high-SF) cycles per degree (c/deg)-which was named pattern glare test. The MDDs group divided into first episode medication-free group (fMDD) and recurrent medicated group (rMDD), comparisons of pattern glare scores (PGS) were performed within the MDDs group. We used Pearson and Spearman analysis to explore the relationship between some clinical indexes and pattern glare scores. ROC (receiver operating characteristic) curve was used to evaluate whether pattern glare test was able to discriminate patients and healthy controls. RESULTS The mid-SF pattern glare score significantly elevated in patients with major depressive disorder compared to control subjects. No differences of pattern glare scores were found between fMDD and rMDD. A significant negative correlation between mid-high difference and age in HCs group was found. There were no correlations between other variables and pattern glare scores. The mid-SF score has limited value in the diagnosis of major depressive disorder. CONCLUSIONS We observed an increased level of pattern glare in patients with major depressive disorder, reflecting the existence of cortical hyper-excitability in major depressive disorder. The mid-SF score may have a value in understanding cortical excitability in major depressive disorder.
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Affiliation(s)
- Xiongwei Qi
- 0000 0004 1770 1022grid.412901.fPsychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610064 People’s Republic of China
| | - Huanhuan Fan
- 0000 0004 1770 1022grid.412901.fPsychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610064 People’s Republic of China
| | - Xiao Yang
- 0000 0004 1770 1022grid.412901.fPsychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610064 People’s Republic of China
| | - Yayun Chen
- 0000 0004 1770 1022grid.412901.fPsychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610064 People’s Republic of China
| | - Wei Deng
- 0000 0004 1770 1022grid.412901.fPsychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610064 People’s Republic of China ,0000 0004 1770 1022grid.412901.fWest China Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
| | - Wanjun Guo
- 0000 0004 1770 1022grid.412901.fPsychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610064 People’s Republic of China ,0000 0004 1770 1022grid.412901.fWest China Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
| | - Qiang Wang
- 0000 0004 1770 1022grid.412901.fPsychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610064 People’s Republic of China ,0000 0004 1770 1022grid.412901.fWest China Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
| | - Eric Chen
- Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong
| | - Tao Li
- 0000 0004 1770 1022grid.412901.fPsychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan 610064 People’s Republic of China ,0000 0004 1770 1022grid.412901.fWest China Brain Research Center, West China Hospital of Sichuan University, Chengdu, China
| | - Xiaohong Ma
- Psychiatric Laboratory and Mental Health Center, West China Hospital of Sichuan University, Chengdu, Sichuan, 610064, People's Republic of China. .,West China Brain Research Center, West China Hospital of Sichuan University, Chengdu, China.
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Abdelkarim D, Zhao Y, Turner MP, Sivakolundu DK, Lu H, Rypma B. A neural-vascular complex of age-related changes in the human brain: Anatomy, physiology, and implications for neurocognitive aging. Neurosci Biobehav Rev 2019; 107:927-944. [DOI: 10.1016/j.neubiorev.2019.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 08/02/2019] [Accepted: 09/02/2019] [Indexed: 01/09/2023]
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20
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Saito M, Odajima S, Yokomizo R, Tabata J, Iida Y, Ueda K, Yanaihara N, Yamada K, Okamoto A. A simple method of quantifying chemotherapy-induced peripheral neuropathy using PainVision PS-2100 ®. Asia Pac J Clin Oncol 2019; 16:80-85. [PMID: 31774247 DOI: 10.1111/ajco.13293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 10/26/2019] [Indexed: 11/26/2022]
Abstract
AIM This study aimed to validate a simplified method of quantifying chemotherapy-induced peripheral neuropathy using the PainVision PS-2100® (PV) electrical perception system. METHODS We assessed patients diagnosed with epithelial ovarian cancer, fallopian tube cancer, or peritoneal cancer and were about to undergo first-time paclitaxel and carboplatin chemotherapy. Peripheral neuropathy was assessed before and after chemotherapy administration in all patients according to the National Cancer Institute-Common Terminology Criteria for Adverse Events Version 4.0 (NCI-CTCAE4.0), using a conventional assessment in combination with the PV system. The PV device comprises electrodes attached to the ulnar side of the forearm and the first joint of index fingers on both the left and right sides to measure the electrical perceptual threshold. The average of three threshold measurements was recorded for each patient. RESULTS Thirty female patients (age 51.6 ± 12.2 [mean ± SD]) were included, and median number of chemotherapy drug treatments was 5 (first quartile: 4, second quartile: 5, and third quartile: 5). Twenty-seven patients (90%) reported posttreatment numbness; NCI-CTCAE4.0 perceptual anomaly grades were as follows: G1, 57 (40%); G2, 19 (13%); and G3, 7 (5%). A positive correlation was identified between right medial side PV threshold score and perceptual anomaly grade on measurements of the inner right-hand side only. CONCLUSION Our preliminary results suggest that peripheral neuropathy may be quantified using PV. As CIPN often lowers QOL, it needs to be appropriately evaluated. Future studies with a larger patient cohort and methodological refinements to improve accuracy are warranted.
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Affiliation(s)
- Motoaki Saito
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Suguru Odajima
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Ryo Yokomizo
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Jyunya Tabata
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Yasushi Iida
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kazu Ueda
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Nozomu Yanaihara
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kyosuke Yamada
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Aikou Okamoto
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
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Marin MA, Carmichael ST. Mechanisms of demyelination and remyelination in the young and aged brain following white matter stroke. Neurobiol Dis 2019; 126:5-12. [DOI: 10.1016/j.nbd.2018.07.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/03/2018] [Accepted: 07/18/2018] [Indexed: 01/01/2023] Open
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22
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Galloway DA, Phillips AEM, Owen DRJ, Moore CS. Phagocytosis in the Brain: Homeostasis and Disease. Front Immunol 2019; 10:790. [PMID: 31040847 PMCID: PMC6477030 DOI: 10.3389/fimmu.2019.00790] [Citation(s) in RCA: 172] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/26/2019] [Indexed: 12/28/2022] Open
Abstract
Microglia are resident macrophages of the central nervous system and significantly contribute to overall brain function by participating in phagocytosis during development, homeostasis, and diseased states. Phagocytosis is a highly complex process that is specialized for the uptake and removal of opsonized and non-opsonized targets, such as pathogens, apoptotic cells, and cellular debris. While the role of phagocytosis in mediating classical innate and adaptive immune responses has been known for decades, it is now appreciated that phagocytosis is also critical throughout early neural development, homeostasis, and initiating repair mechanisms. As such, modulating phagocytic processes has provided unexplored avenues with the intent of developing novel therapeutics that promote repair and regeneration in the CNS. Here, we review the functional consequences that phagocytosis plays in both the healthy and diseased CNS, and summarize how phagocytosis contributes to overall pathophysiological mechanisms involved in brain injury and repair.
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Affiliation(s)
- Dylan A Galloway
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Alexandra E M Phillips
- Division of Brain Sciences, Department of Medicine Hammersmith Hospital, Imperial College London, London, United Kingdom
| | - David R J Owen
- Division of Brain Sciences, Department of Medicine Hammersmith Hospital, Imperial College London, London, United Kingdom
| | - Craig S Moore
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
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23
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Berman S, Filo S, Mezer AA. Modeling conduction delays in the corpus callosum using MRI-measured g-ratio. Neuroimage 2019; 195:128-139. [PMID: 30910729 DOI: 10.1016/j.neuroimage.2019.03.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/12/2019] [Accepted: 03/12/2019] [Indexed: 11/26/2022] Open
Abstract
Conduction of action potentials along myelinated axons is affected by their structural features, such as the axonal g-ratio, the ratio between the inner and outer diameters of the myelin sheath surrounding the axon. The effect of g-ratio variance on conduction properties has been quantitatively evaluated using single-axon models. It has recently become possible to estimate a g-ratio weighted measurement in vivo using quantitative MRI. Nevertheless, it is still unclear whether the variance in the g-ratio in the healthy human brain leads to significant differences in conduction velocity. In this work we tested whether the g-ratio MRI measurement can be used to predict conduction delays in the corpus callosum. We present a comprehensive framework in which the structural properties of fibers (i.e. length and g-ratio, measured using MRI), are incorporated in a biophysical model of axon conduction, to model conduction delays of long-range white matter fibers. We applied this framework to the corpus callosum, and found conduction delay estimates that are compatible with previously estimated values of conduction delays. We account for the variance in the velocity given the axon diameter distribution in the splenium, mid-body and genu, to further compare the fibers within the corpus callosum. Conduction delays have been suggested to increase with age. Therefore, we investigated whether there are differences in the g-ratio and the fiber length between young and old adults, and whether this leads to a difference in conduction speed and delays. We found very small differences between the predicted delays of the two groups in the motor fibers of the corpus callosum. We also found that the motor fibers of the corpus callosum have the fastest conduction estimates. Using the axon diameter distributions, we found that the occipital fibers have the slowest estimations, while the frontal and motor fiber tracts have similar estimates. Our study provides a framework for predicting conduction latencies in vivo. The framework could have major implications for future studies of white matter diseases and large range network computations. Our results highlight the need for improving additional in vivo measurements of white matter microstructure.
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Affiliation(s)
- S Berman
- Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - S Filo
- Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - A A Mezer
- Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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24
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Metwally E, Farouk SM, Hossain MS, Raihan O. Expression of glial cells molecules in the optic nerve of adult dromedary camel (Camelus dromedarius): A histological and immunohistochemical analysis. Anat Histol Embryol 2018; 48:74-86. [DOI: 10.1111/ahe.12413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 10/12/2018] [Accepted: 10/19/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Elsayed Metwally
- State Key Laboratory of Molecular Development Biology, Institute of Genetics & Developmental Biology; Chinese Academy of Sciences; Beijing China
- Department of Cytology & Histology, Faculty of Veterinary Medicine; Suez Canal University; Ismailia Egypt
| | - Sameh M. Farouk
- Department of Cytology & Histology, Faculty of Veterinary Medicine; Suez Canal University; Ismailia Egypt
| | - Md Shafayat Hossain
- State Key Laboratory of Molecular Development Biology, Institute of Genetics & Developmental Biology; Chinese Academy of Sciences; Beijing China
| | - Obayed Raihan
- Jessore University of Science and Technology; Jessore Bangladesh
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25
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Xu M, Wang MM, Gao Y, Keep RF, Shi Y. The effect of age-related risk factors and comorbidities on white matter injury and repair after ischemic stroke. Neurobiol Dis 2018; 126:13-22. [PMID: 30017454 DOI: 10.1016/j.nbd.2018.07.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/17/2018] [Accepted: 07/10/2018] [Indexed: 02/06/2023] Open
Abstract
White matter injury is a crucial component of human stroke, but it has often been neglected in preclinical studies. Most human stroke is associated with one or more comorbidities, including aging, hypertension, diabetes and metabolic syndrome including hyperlipidemia. The purpose of this review is to examine how age and hypertension impact stroke-induced white matter injury as well as white matter repair in both human stroke and preclinical models. It is essential that comorbidities be examined in preclinical trials as they may impact translatability to the clinic. In addition, understanding how comorbidities impact white matter injury and repair may provide new therapeutic opportunities for patients with those conditions.
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Affiliation(s)
- Mingyue Xu
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology, Institute of Brain Sciences and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Michael M Wang
- Departments of Neurology and Physiology, University of Michigan, Ann Arbor, MI 48109, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Yanqin Gao
- State Key Laboratory of Medical Neurobiology, Institute of Brain Sciences and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Richard F Keep
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Yejie Shi
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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26
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Abstract
The primary visual cortex (V1) is the first cortical area that processes visual information. Normal development of V1 depends on binocular vision during the critical period, and age-related losses of vision are linked with neurobiological changes in V1. Animal studies have provided important details about the neurobiological mechanisms in V1 that support normal vision or are changed by visual diseases. There is very little information, however, about those neurobiological mechanisms in human V1. That lack of information has hampered the translation of biologically inspired treatments from preclinical models to effective clinical treatments. We have studied human V1 to characterize the expression of neurobiological mechanisms that regulate visual perception and neuroplasticity. We have identified five stages of development for human V1 that start in infancy and continue across the life span. Here, we describe these stages, compare them with visual and anatomical milestones, and discuss implications for translating treatments for visual disorders that depend on neuroplasticity of V1 function.
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Affiliation(s)
- Caitlin R Siu
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, ON, Canada
| | - Kathryn M Murphy
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, ON, Canada.,Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada
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27
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Al-Bagdadi F, Schumacher J, Carter J, Tóth F, Henry RW. Determining Direction of Axonal Flow in the Equine Ramus Communicans by Ultrastructural Examination of the Plantar Nerves 2 Months after Transecting the Ramus. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2018; 24:64-68. [PMID: 29362000 DOI: 10.1017/s1431927617012818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The ramus communicans, neural connection between medial and lateral plantar nerves of the horse, was transected to determine the degree to which medial and lateral plantar nerves contribute to the plantar ramus. After 2 months, sections of plantar nerves immediately proximal and distal to the communicating branch were collected and processed for electron microscopy. All examined nerves had undergone Wallerian degeneration and contained regenerating and mature fibers. Layers of the myelin sheath were separated by spaces and vacuoles, indicating demyelination of medial and lateral plantar nerves. Shrunken axons varied in diameter and were surrounded by an irregular axolemma. Shrunken axoplasm of both myelinated and non-myelinated fibers contained ruptured mitochondria and cristae, disintegrating cytoskeleton, and vacuoles of various sizes. The cytoplasm of neurolemmocytes contained various-sized vesicles, ruptured mitochondria within a fragile basal lamina and myelin whorls of multilayered structures indicative of Wallerian degeneration. These ultrastructural changes, found proximal and distal to the ramus in medial and lateral plantar nerves, suggest that axonal flow is bi-directional through the ramus communicans of the pelvic limbs of horses, a previously unreported finding. As well, maturity of nerves proximal and distal to the ramus indicates that all nerve fibers do not pass through the ramus.
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Affiliation(s)
- Fakhri Al-Bagdadi
- 1Department of Comparative Biomedical Sciences,School of Veterinary Medicine,Louisiana State University,Baton Rouge,LA 70803,USA
| | - Jim Schumacher
- 2Department of Large Animal Clinical Sciences,College of Veterinary Medicine,University of Tennessee,Knoxville,TN 37996,USA
| | - Jessi Carter
- 2Department of Large Animal Clinical Sciences,College of Veterinary Medicine,University of Tennessee,Knoxville,TN 37996,USA
| | - Ferenc Tóth
- 2Department of Large Animal Clinical Sciences,College of Veterinary Medicine,University of Tennessee,Knoxville,TN 37996,USA
| | - Robert W Henry
- 3College of Veterinary Medicine,Lincoln Memorial University,Harrogate,TN 37752,USA
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28
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Robinson AA, Abraham CR, Rosene DL. Candidate molecular pathways of white matter vulnerability in the brain of normal aging rhesus monkeys. GeroScience 2018; 40:31-47. [PMID: 29357021 PMCID: PMC5832663 DOI: 10.1007/s11357-018-0006-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 01/08/2018] [Indexed: 12/20/2022] Open
Abstract
Mammalian aging is associated with decline in cognitive functions. Studies searching for a cause of cognitive aging initially focused on neuronal loss but quantitative investigations of rat, monkey, and human brain using stereology demonstrated that in normal aging, unlike in neurodegenerative disease, neurons are not lost. Instead, electron microscopic and MRI studies in normal aging monkeys revealed age-related damage to myelin sheaths, loss of axons, and reduction in white matter volume which correlates with cognitive impairments. However, little is known about the cause of myelin defects or associated axon loss. The present study investigates the effect of age on signaling pathways between oligodendroglia and neurons using a custom PCR array to assess the expression of 87 genes of interest in cortical gray matter and white matter from the inferior parietal lobe (IPL) of normal rhesus monkeys ranging in age from 4.2 to 30.4 years old. From this array data, five target genes of interest were selected for further analysis to confirm gene expression and measure protein expression. The most interesting target gene identified is brain-derived neurotrophic factor (BDNF), which was the only gene that was altered at both mRNA and protein levels. In gray matter, BDNF mRNA was decreased. While the level of the mature form of the protein was unchanged, there was a specific decrease in the precursor form of BDNF. These alterations in the BDNF in gray matter could contribute to the vulnerability and loss of the axons with age.
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Affiliation(s)
- Amy A. Robinson
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118 USA
| | - Carmela R. Abraham
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118 USA
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118 USA
| | - Douglas L. Rosene
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118 USA
- Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322 USA
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29
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Age-dependent differences in myelin basic protein expression in the hippocampus of young, adult and aged gerbils. Lab Anim Res 2017; 33:237-243. [PMID: 29046699 PMCID: PMC5645602 DOI: 10.5625/lar.2017.33.3.237] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 11/21/2022] Open
Abstract
Myelin degeneration is one of the characteristics of aging and degenerative diseases. This study investigated age-related alterations in expression of myelin basic protein (MBP) in the hippocampal subregions (dentate gyrus, CA2/3 and CA1 areas) of gerbils of various ages; young (1 month), adult (6 months) and aged (24 months), using western blot and immunohistochemistry. Western blot results showed tendencies of age-related reductions of MBP levels. MBP immunoreactivity was significantly decreased with age in synaptic sites of trisynaptic loops, perforant paths, mossy fibers, and Schaffer collaterals. In particular, MBP immunoreactive fibers in the dentate molecular cell layer (perforant path) was significantly reduced in adult and aged subjects. In addition, MBP immunoreactive mossy fibers in the dentate polymorphic layer and in the CA3 striatum radiatum was significantly decreased in the aged group. Furthermore, we observed similar age-related alterations in the CA1 stratum radiatum (Schaffer collaterals). However, the density of MBP immunoreactive fibers in the dentate granular cell layer and CA stratum pyramidale was decreased with aging. These findings indicate that expression of MBP is age-dependent and tissue specific according to hippocampal layers.
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30
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Moore TL, Bowley B, Shultz P, Calderazzo S, Shobin E, Killiany RJ, Rosene DL, Moss MB. Chronic curcumin treatment improves spatial working memory but not recognition memory in middle-aged rhesus monkeys. GeroScience 2017; 39:571-584. [PMID: 29047012 DOI: 10.1007/s11357-017-9998-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 10/02/2017] [Indexed: 12/15/2022] Open
Abstract
Studies of both humans and non-human primates have demonstrated that aging is typically characterized by a decline in cognition that can occur as early as the fifth decade of life. Age-related changes in working memory are particularly evident and mediated, in part, by the prefrontal cortex, an area known to evidence age-related changes in myelin that is attributed to inflammation. In recent years, several nutraceuticals, including curcumin, by virtue of their anti-inflammatory and antioxidant effects, have received considerable attention as potential treatments for age-related cognitive decline and inflammation. Accordingly, we assessed for the first time in a non-human primate model of normal aging the efficacy of dietary intervention using the natural phenol curcumin to ameliorate the effects of aging on spatial working and recognition memory. Results revealed that monkeys receiving daily administration of curcumin over 14-18 months demonstrated a greater improvement in performance on repeated administration of a task of spatial working memory compared to monkeys that received a control substance.
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Affiliation(s)
- Tara L Moore
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 E. Concord Street, L-1004, Boston, MA, 02118, USA.
- Department of Neurology, Boston University School of Medicine, 725 Albany Street, Boston, MA, 02118, USA.
| | - Bethany Bowley
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 E. Concord Street, L-1004, Boston, MA, 02118, USA
| | - Penny Shultz
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 E. Concord Street, L-1004, Boston, MA, 02118, USA
| | - Samantha Calderazzo
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 E. Concord Street, L-1004, Boston, MA, 02118, USA
| | - Eli Shobin
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 E. Concord Street, L-1004, Boston, MA, 02118, USA
- Graduate Program in Neuroscience, Boston University School of Medicine, 72 E. Concord Street, Boston, MA, 02118, USA
| | - Ronald J Killiany
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 E. Concord Street, L-1004, Boston, MA, 02118, USA
- Department of Neurology, Boston University School of Medicine, 725 Albany Street, Boston, MA, 02118, USA
| | - Douglas L Rosene
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 E. Concord Street, L-1004, Boston, MA, 02118, USA
- Yerkes National Primate Research Center, Emory University, 201 Dowman Drive, Atlanta, GA, 30322, USA
| | - Mark B Moss
- Department of Anatomy & Neurobiology, Boston University School of Medicine, 72 E. Concord Street, L-1004, Boston, MA, 02118, USA
- Department of Neurology, Boston University School of Medicine, 725 Albany Street, Boston, MA, 02118, USA
- Yerkes National Primate Research Center, Emory University, 201 Dowman Drive, Atlanta, GA, 30322, USA
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31
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Berman S, West KL, Does MD, Yeatman JD, Mezer AA. Evaluating g-ratio weighted changes in the corpus callosum as a function of age and sex. Neuroimage 2017; 182:304-313. [PMID: 28673882 DOI: 10.1016/j.neuroimage.2017.06.076] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 11/16/2022] Open
Abstract
Recent years have seen a growing interest in relating MRI measurements to the structural-biophysical properties of white matter fibers. The fiber g-ratio, defined as the ratio between the inner and outer radii of the axon myelin sheath, is an important structural property of white matter, affecting signal conduction. Recently proposed modeling methods that use a combination of quantitative-MRI signals, enable a measurement of the fiber g-ratio in vivo. Here we use an MRI-based g-ratio estimation to observe the variance of the g-ratio within the corpus callosum, and evaluate sex and age related differences. To estimate the g-ratio we used a model (Stikov et al., 2011; Duval et al., 2017) based on two different WM microstructure parameters: the relative amounts of myelin (myelin volume fraction, MVF) and fibers (fiber volume fraction, FVF) in a voxel. We derived the FVF from the fractional anisotropy (FA), and estimated the MVF by using the lipid and macromolecular tissue volume (MTV), calculated from the proton density (Mezer et al., 2013). In comparison to other methods of estimating the MVF, MTV represents a stable parameter with a straightforward route of acquisition. To establish our model, we first compared histological MVF measurements (West et al., 2016) with the MRI derived MTV. We then implemented our model on a large database of 92 subjects (44 males), aged 7 to 81, in order to evaluate age and sex related changes within the corpus callosum. Our results show that the MTV provides a good estimation of MVF for calculating g-ratio, and produced values from the corpus callosum that correspond to those found in animals ex vivo and are close to the theoretical optimum, as well as to published in vivo data. Our results demonstrate that the MTV derived g-ratio provides a simple and reliable in vivo g-ratio-weighted (GR*) measurement in humans. In agreement with theoretical predictions, and unlike other tissue parameters measured with MRI, the g-ratio estimations were found to be relatively stable with age, and we found no support for a significant sexual dimorphism with age.
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Affiliation(s)
- Shai Berman
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Kathryn L West
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
| | - Mark D Does
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
| | - Jason D Yeatman
- Institute for Learning & Brain Sciences and Department of Speech & Hearing Sciences, University of Washington, Seattle, WA, USA
| | - Aviv A Mezer
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
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32
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Rowley CD, Sehmbi M, Bazin PL, Tardif CL, Minuzzi L, Frey BN, Bock NA. Age-related mapping of intracortical myelin from late adolescence to middle adulthood using T 1 -weighted MRI. Hum Brain Mapp 2017; 38:3691-3703. [PMID: 28462512 DOI: 10.1002/hbm.23624] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/10/2017] [Accepted: 04/12/2017] [Indexed: 12/11/2022] Open
Abstract
Magnetic resonance imaging (MRI) studies in humans have reported that the T1 -weighted signal in the cerebral cortex follows an inverted "U" trajectory over the lifespan. Here, we investigated the T1 -weighted signal trajectory from late adolescence to middle adulthood in humans to characterize the age range when mental illnesses tend to present, and efficacy of treatments are evaluated. We compared linear to quadratic predictors of age on signal in 67 healthy individuals, 17-45 years old. We investigated ¼, ½, and ¾ depths in the cortex representing intracortical myelin (ICM), in the superficial white matter (SWM), and in a reference deep white matter tract. We found that the quadratic fit was superior in all regions of the cortex, while signal in the SWM and deep white matter showed no global dependence on age over this range. The signal trajectory in any region followed a similar shape regardless of cortical depth. The quadratic fit was analyzed in 70 cortical regions to obtain the age of maximum signal intensity. We found that visual, cingulate, and left ventromedial prefrontal cortices peak first around 34 years old, whereas motor and premotor areas peak latest at ∼38 years. Our analysis suggests that ICM trajectories over this range can be modeled well in small cohorts of subjects using quadratic functions, which are amenable to statistical analysis, thus suitable for investigating regional changes in ICM with disease. This study highlights a novel approach to map ICM trajectories using an age range that coincides with the onset of many mental illnesses. Hum Brain Mapp 38:3691-3703, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Christopher D Rowley
- McMaster Integrative Neuroscience Discovery and Study Program, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
| | - Manpreet Sehmbi
- McMaster Integrative Neuroscience Discovery and Study Program, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
| | - Pierre-Louis Bazin
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, 04103, Germany
| | - Christine L Tardif
- Brain Imaging Centre, Douglas Mental Health Institute; Department of Psychiatry, McGill University, Montreal, Quebec, H4H 1R3, Canada
| | - Luciano Minuzzi
- McMaster Integrative Neuroscience Discovery and Study Program, McMaster University, Hamilton, Ontario, L8S 4K1, Canada.,Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, L8S 4K1, Canada.,Mood Disorders Program and Women's Health Concerns Clinic, St. Joseph's Healthcare, Hamilton, Ontario, L8K 3K7, Canada
| | - Benicio N Frey
- McMaster Integrative Neuroscience Discovery and Study Program, McMaster University, Hamilton, Ontario, L8S 4K1, Canada.,Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, L8S 4K1, Canada.,Mood Disorders Program and Women's Health Concerns Clinic, St. Joseph's Healthcare, Hamilton, Ontario, L8K 3K7, Canada
| | - Nicholas A Bock
- McMaster Integrative Neuroscience Discovery and Study Program, McMaster University, Hamilton, Ontario, L8S 4K1, Canada.,Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
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Shobin E, Bowley MP, Estrada LI, Heyworth NC, Orczykowski ME, Eldridge SA, Calderazzo SM, Mortazavi F, Moore TL, Rosene DL. Microglia activation and phagocytosis: relationship with aging and cognitive impairment in the rhesus monkey. GeroScience 2017; 39:199-220. [PMID: 28238188 PMCID: PMC5411373 DOI: 10.1007/s11357-017-9965-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 02/07/2017] [Indexed: 02/07/2023] Open
Abstract
While cognitive decline is observed in the normal aging monkey, neurons are not lost with age. Instead, frontal white matter is lost as myelin degenerates and both correlate with age-related cognitive decline. As age-related myelin damage increases, there should be an increase in clearance of damaged myelin by microglial phagocytosis. In this study, brains of behaviorally tested rhesus monkeys were assessed using unbiased stereology to quantify the density of activated microglia (LN3 antibody positive) and phagocytic microglia (galectin-3 (Gal-3) antibody positive) in three white matter regions: the corpus callosum, cingulum bundle (CGB), and frontal white matter (FWM). LN3 cell density was significantly increased in the CGB, whereas Gal-3 cell density was significantly increased in all regions. Increases in Gal-3 cell density in the FWM were associated with cognitive impairment. In the FWM of old animals, Gal-3-positive microglia were classified by morphological subtype as ramified, hypertrophic, or amoeboid. The densities of hypertrophic and amoeboid microglia significantly correlated with cognitive impairment. Finally, microglia were double-labeled with LN3 and Gal-3 showing that 91% of Gal-3 cells were also LN3 positive, thus expressing an "activated" phenotype. Furthermore, 15% of all double-labeled cells formed phagocytic cups. Overall, these results suggest that microglia become activated in white matter with age where the majority express a phagocytic phenotype. We hypothesize that age-related phagocytic activation of microglia is a response to accumulating myelin pathology. The association of Gal-3 in the FWM with cognitive impairment may reflect regional differences in damage or dysfunction of normal clearance mechanisms.
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Affiliation(s)
- Eli Shobin
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, 02118, USA.
- Graduate Program for Neuroscience, Boston University, Boston, MA, 02118, USA.
| | - Michael P Bowley
- Department of Neurology, Massachusetts General Hospital, Boston, MA, 02144, USA
| | - Larissa I Estrada
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, 02118, USA
- Department of Pharmacology and Experimental Therapeutics, Boston University, Boston, MA, 02118, USA
| | - Nadine C Heyworth
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, 02118, USA
| | - Mary E Orczykowski
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, 02118, USA
| | - Sherri A Eldridge
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, 02118, USA
- Biology Department, University of Massachusetts Dartmouth, Dartmouth, MA, 02747, USA
| | | | - Farzad Mortazavi
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, 02118, USA
| | - Tara L Moore
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, 02118, USA
- Department of Neurology, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Douglas L Rosene
- Department of Anatomy and Neurobiology, Boston University, Boston, MA, 02118, USA
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Hsu A, Luebke JI, Medalla M. Comparative ultrastructural features of excitatory synapses in the visual and frontal cortices of the adult mouse and monkey. J Comp Neurol 2017; 525:2175-2191. [PMID: 28256708 DOI: 10.1002/cne.24196] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/18/2017] [Accepted: 02/10/2017] [Indexed: 01/20/2023]
Abstract
The excitatory glutamatergic synapse is the principal site of communication between cortical pyramidal neurons and their targets, a key locus of action of many drugs, and highly vulnerable to dysfunction and loss in neurodegenerative disease. A detailed knowledge of the structure of these synapses in distinct cortical areas and across species is a prerequisite for understanding the anatomical underpinnings of cortical specialization and, potentially, selective vulnerability in neurological disorders. We used serial electron microscopy to assess the ultrastructural features of excitatory (asymmetric) synapses in the layers 2-3 (L2-3) neuropil of visual (V1) and frontal (FC) cortices of the adult mouse and compared findings to those in the rhesus monkey (V1 and lateral prefrontal cortex [LPFC]). Analyses of multiple ultrastructural variables revealed four organizational features. First, the density of asymmetric synapses does not differ between frontal and visual cortices in either species, but is significantly higher in mouse than in monkey. Second, the structural properties of asymmetric synapses in mouse V1 and FC are nearly identical, by stark contrast to the significant differences seen between monkey V1 and LPFC. Third, while the structural features of postsynaptic entities in mouse and monkey V1 do not differ, the size of presynaptic boutons are significantly larger in monkey V1. Fourth, both presynaptic and postsynaptic entities are significantly smaller in the mouse FC than in the monkey LPFC. The diversity of synaptic ultrastructural features demonstrated here have broad implications for the nature and efficacy of glutamatergic signaling in distinct cortical areas within and across species.
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Affiliation(s)
- Alexander Hsu
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts
| | - Jennifer I Luebke
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts
| | - Maria Medalla
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts
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Stereological quantification of age-related changes in myelinated fibers of rat white matter. Neuroreport 2017; 28:42-49. [PMID: 27902556 DOI: 10.1097/wnr.0000000000000706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We investigated changes in myelin sheaths in the myelinated fibers of subcortical white matter in young (6-8 months old), middle-aged (18 months old), and elderly (27-28 months old) female Long-Evans rats using transmission electron microscopy and unbiased stereological techniques. We observed three age-related changes in myelin sheaths in the white matter of elderly rats: local splitting of the major dense line, myelin ballooning, and the formation of abundant myelin sheaths. Stereological analysis showed that the total length of myelinated fibers in white matter was 115±12 km (mean±SD) in young rats, 135±21 km in middle-aged rats, and 62±11 km in elderly rats. Myelinated fibers with diameters less than 1.0 μm and myelin sheath thicknesses less than 0.1 μm were significantly shorter in middle-aged and elderly rats compared with young rats. Age-related changes in myelin sheaths were evident in aged white matter. The loss of myelinated fibers with both small diameters and thin myelin sheaths is a potentially important change in aged white matter. Our results suggest that the myelin sheath changes in aged white matter may have important implications for age-related cognitive impairments.
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36
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The COMT Val158Met polymorphism moderates the association between cognitive functions and white matter microstructure in schizophrenia. Psychiatr Genet 2016; 26:193-202. [DOI: 10.1097/ypg.0000000000000130] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Age-Related Changes in Axonal and Mitochondrial Ultrastructure and Function in White Matter. J Neurosci 2016; 36:9990-10001. [PMID: 27683897 DOI: 10.1523/jneurosci.1316-16.2016] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/02/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The impact of aging on CNS white matter (WM) is of general interest because the global effects of aging on myelinated nerve fibers are more complex and profound than those in cortical gray matter. It is important to distinguish between axonal changes created by normal aging and those caused by neurodegenerative diseases, including multiple sclerosis, stroke, glaucoma, Alzheimer's disease, and traumatic brain injury. Using three-dimensional electron microscopy, we show that in mouse optic nerve, which is a pure and fully myelinated WM tract, aging axons are larger, have thicker myelin, and are characterized by longer and thicker mitochondria, which are associated with altered levels of mitochondrial shaping proteins. These structural alterations in aging mitochondria correlate with lower ATP levels and increased generation of nitric oxide, protein nitration, and lipid peroxidation. Moreover, mitochondria-smooth endoplasmic reticulum interactions are compromised due to decreased associations and decreased levels of calnexin and calreticulin, suggesting a disruption in Ca(2+) homeostasis and defective unfolded protein responses in aging axons. Despite these age-related modifications, axon function is sustained in aging WM, which suggests that age-dependent changes do not lead to irreversible functional decline under normal conditions, as is observed in neurodegenerative diseases. SIGNIFICANCE STATEMENT Aging is a common risk factor for a number of neurodegenerative diseases, including stroke. Mitochondrial dysfunction and oxidative damage with age are hypothesized to increase risk for stroke. We compared axon-myelin-node-mitochondrion-smooth endoplasmic reticulum (SER) interactions in white matter obtained at 1 and 12 months. We show that aging axons have enlarged volume, thicker myelin, and elongated and thicker mitochondria. Furthermore, there are reduced SER connections to mitochondria that correlate with lower calnexin and calreticulin levels. Despite a prominent decrease in number, elongated aging mitochondria produce excessive stress markers with reduced ATP production. Because axons maintain function under these conditions, our study suggests that it is important to understand the process of normal brain aging to identify neurodegenerative changes.
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Zhan X, Jickling GC, Ander BP, Stamova B, Liu D, Kao PF, Zelin MA, Jin LW, DeCarli C, Sharp FR. Myelin basic protein associates with AβPP, Aβ1-42, and amyloid plaques in cortex of Alzheimer's disease brain. J Alzheimers Dis 2015; 44:1213-29. [PMID: 25697841 DOI: 10.3233/jad-142013] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The goal of this study was to show that myelin and axons in cortical gray matter are damaged in Alzheimer's disease (AD) brain. Superior temporal gyrus gray matter of AD patients (9 male, 14 female) was compared to cognitively normal controls (8 male, 7 female). Myelin basic protein (MBP) and a degraded myelin basic protein complex (dMBP) were quantified by Western blot. Brain sections were immunostained for MBP, dMBP, axonal neurofilament protein (NF), autophagy marker microtubule-associated proteins 1A/B light chain 3B precursor (LC3B), amyloid-β protein precursor (AβPP), and amyloid markers amyloid β1-42 (Aβ1-42) and FSB. Co-immunoprecipitation and mass spectroscopy evaluated interaction of AβPP/Aβ1-42 with MBP/dMBP. Evidence of axonal injury in AD cortex included appearance of AβPP in NF stained axons, and NF at margins of amyloid plaques. Evidence of myelin injury in AD cortex included (1) increased dMBP in AD gray matter compared to control (p < 0.001); (2) dMBP in AD neurons; and (3) increased LC3B that co-localized with MBP. Evidence of interaction of AβPP/Aβ1-42 with myelin or axonal components included (1) greater binding of dMBP with AβPP in AD brain; (2) MBP at the margins of amyloid plaques; (3) dMBP co-localized with Aβ1-42 in the core of amyloid plaques in AD brains; and (4) interactions between Aβ1-42 and MBP/dMBP by co-immunoprecipitation and mass spectrometry. We conclude that damaged axons may be a source of AβPP. dMBP, MBP, and NF associate with amyloid plaques and dMBP associates with AβPP and Aβ1-42. These molecules could be involved in formation of amyloid plaques.
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Affiliation(s)
- Xinhua Zhan
- Department of Neurology, MIND Institute, University of California at Davis, Sacramento, CA, USA
| | - Glen C Jickling
- Department of Neurology, MIND Institute, University of California at Davis, Sacramento, CA, USA
| | - Bradley P Ander
- Department of Neurology, MIND Institute, University of California at Davis, Sacramento, CA, USA
| | - Boryana Stamova
- Department of Neurology, MIND Institute, University of California at Davis, Sacramento, CA, USA
| | - DaZhi Liu
- Department of Neurology, MIND Institute, University of California at Davis, Sacramento, CA, USA
| | - Patricia F Kao
- Alzheimer's Disease Center, University of California at Davis, Sacramento, CA, USA Department of Pathology, University of California at Davis, Sacramento, CA, USA
| | - Mariko A Zelin
- Alzheimer's Disease Center, University of California at Davis, Sacramento, CA, USA Department of Pathology, University of California at Davis, Sacramento, CA, USA
| | - Lee-Way Jin
- Alzheimer's Disease Center, University of California at Davis, Sacramento, CA, USA Department of Pathology, University of California at Davis, Sacramento, CA, USA
| | - Charles DeCarli
- Department of Neurology, MIND Institute, University of California at Davis, Sacramento, CA, USA Alzheimer's Disease Center, University of California at Davis, Sacramento, CA, USA
| | - Frank R Sharp
- Department of Neurology, MIND Institute, University of California at Davis, Sacramento, CA, USA
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Zhu F, Gatti DL, Yang KH. Nodal versus Total Axonal Strain and the Role of Cholesterol in Traumatic Brain Injury. J Neurotrauma 2015; 33:859-70. [PMID: 26393780 DOI: 10.1089/neu.2015.4007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traumatic brain injury (TBI) is a health threat that affects every year millions of people involved in motor vehicle and sporting accidents, and thousands of soldiers in battlefields. Diffuse axonal injury (DAI) is one of the most frequent types of TBI leading to death. In DAI, the initial traumatic event is followed by a cascade of biochemical changes that take time to develop in full, so that symptoms may not become apparent until days or weeks after the original injury. Hence, DAI is a dynamic process, and the opportunity exists to prevent its progression provided the initial trauma can be predicted at the molecular level. Here, we present preliminary evidence from micro-finite element (FE) simulations that the mechanical response of central nervous system myelinated fibers is dependent on the axonal diameter, the ratio between axon diameter and fiber diameter (g-ratio), the microtubules density, and the cholesterol concentration in the axolemma and myelin. A key outcome of the simulations is that there is a significant difference between the overall level of strain in a given axonal segment and the level of local strain in the Ranvier nodes contained in that segment, with the nodal strain being much larger than the total strain. We suggest that the acquisition of this geometric and biochemical information by means of already available high resolution magnetic resonance imaging techniques, and its incorporation in current FE models of the brain will enhance the models capacity to predict the site and magnitude of primary axonal damage upon TBI.
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Affiliation(s)
- Feng Zhu
- 1 Department of Biomedical Engineering, Wayne State University , Detroit, Michigan
| | - Domenico L Gatti
- 2 Department of Biochemistry and Molecular Biology, Wayne State University , Detroit, Michigan.,3 CardioVascular Research Institute, Wayne State University , Detroit, Michigan
| | - King H Yang
- 1 Department of Biomedical Engineering, Wayne State University , Detroit, Michigan
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40
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Dupree JL, Polak PE, Hensley K, Pelligrino D, Feinstein DL. Lanthionine ketimine ester provides benefit in a mouse model of multiple sclerosis. J Neurochem 2015; 134:302-14. [PMID: 25846048 DOI: 10.1111/jnc.13114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/26/2015] [Accepted: 03/27/2015] [Indexed: 01/26/2023]
Abstract
Lanthionine ketimine (LK) is a natural sulfur amino acid metabolite which binds to collapsin response mediator protein-2 (CRMP2), an abundant brain protein that interacts with multiple partners to regulate microtubule dynamics, neurite growth and retraction, axonal transport, and neurotransmitter release. LK ethyl-ester (LKE) is a cell-permeable synthetic derivative that promotes neurogenesis, suppresses nitric oxide production from microglia, and reduces neurotoxicity of microglia-conditioned medium. These properties led us to test the effects of LKE in experimental autoimmune encephalomyelitis (EAE), a commonly used mouse model of multiple sclerosis. Female C57Bl/6 mice were immunized with myelin oligodendrocyte glycoprotein peptide 35-55 to develop a chronic disease. LKE was provided in the chow at 100 ppm, ad libitum beginning when the mice reached moderate clinical signs. Over the following 4 weeks the LKE-treated mice showed a significant reduction in clinical signs compared to vehicle-treated mice. LKE dose dependently reduced IFNγ production from splenic T cells, but had no effect on IL-17 production suggesting protective effects were mediated within the CNS. Electron microscopy revealed that, compared to sham mice, EAE mice had significant neurodegeneration in both the optic nerve and spinal cord, which was reduced in the LKE-treated mice. In contrast only minimal disruption of myelin was observed at this time point. In the optic nerve, measurements of axon caliber and myelin thickness showed little changes between sham and EAE mice, however, treatment with LKE increased the percentage of axons with thicker myelin and with larger axon calibers. In the spinal cord, only smaller effects of LKE on myelin thickness were observed. The effects of LKE were associated with a reduced relative level of phosphorylated CRMP2 to CRMP2. Together, these results demonstrate that LKE reduces neurodegeneration in a chronic EAE model of MS, which could have translation potential for treatment of progressive forms of MS.
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Affiliation(s)
- Jeffrey L Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Paul E Polak
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Kenneth Hensley
- Department of Pathology, University of Toledo, College of Medicine, Toledo, Ohio, USA
| | - Dale Pelligrino
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Douglas L Feinstein
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Veterans Affairs, Jesse Brown VA Medical Center, Chicago, Illinois, USA
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41
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Biasibetti E, Bisanzio D, Mioletti S, Amedeo S, Iuliano A, Bianco P, Capucchio MT. Spontaneous Age-related Changes of Peripheral Nerves in Cattle: Morphological and Biochemical Studies. Anat Histol Embryol 2015; 45:100-8. [PMID: 25823666 DOI: 10.1111/ahe.12177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/16/2015] [Indexed: 11/29/2022]
Abstract
Peripheral nerve function is significantly affected by ageing. During ageing process, multiple changes occur on tissue cells and extracellular matrix. The aim of this work was to study the ageing-associated changes of peripheral nerves in adult and old regularly slaughtered cattle compared with young calves, and correlate them to the features reported in humans and laboratory animals. Samples of axial dorsal metacarpal nerves from 44 cows were collected immediately after slaughtering. Each nerve was dissected and divided into two fragments: one used for morphological evaluation (n = 43) and the other one for biochemical analysis (n = 31). Axonal degeneration, demyelination, thickness of perineurium and endoneurium and increase of mast cells were the most important features detected. The mean amount of glycosaminoglycan quantitative content recorded in the samples increased with the age. Axonal degeneration, demyelination and thickness of endoneurium were positively and significantly correlated with biochemistry. The presence of changes affecting the different elements of the peripheral nerves, similar to that reported in humans and in laboratory species, the easy availability of the nerve tissue in this species, the considerable size of the samples and the life conditions more similar to humans than to laboratory animals, allows the authors to consider cattle as a potential good model for the comparative study of spontaneous ageing nerve lesions.
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Affiliation(s)
- E Biasibetti
- Department of Veterinary Sciences, University of Torino, Largo Braccini 2, 10095, Grugliasco, Torino, Italy
| | - D Bisanzio
- Department of Environmental Sciences, Emory University, 400 Dowman Drive, Atlanta, GA, 30322, USA
| | - S Mioletti
- Department of Veterinary Sciences, University of Torino, Largo Braccini 2, 10095, Grugliasco, Torino, Italy
| | - S Amedeo
- Department of Veterinary Sciences, University of Torino, Largo Braccini 2, 10095, Grugliasco, Torino, Italy
| | - A Iuliano
- Department of Veterinary Sciences, University of Torino, Largo Braccini 2, 10095, Grugliasco, Torino, Italy
| | - P Bianco
- ASLTo4, via Po 11, 10034, Chivasso, Torino, Italy
| | - M T Capucchio
- Department of Veterinary Sciences, University of Torino, Largo Braccini 2, 10095, Grugliasco, Torino, Italy
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Diversity of glutamatergic synaptic strength in lateral prefrontal versus primary visual cortices in the rhesus monkey. J Neurosci 2015; 35:112-27. [PMID: 25568107 DOI: 10.1523/jneurosci.3426-14.2015] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Understanding commonalities and differences in glutamatergic synaptic signaling is essential for understanding cortical functional diversity, especially in the highly complex primate brain. Previously, we have shown that spontaneous EPSCs differed markedly in layer 3 pyramidal neurons of two specialized cortical areas in the rhesus monkey, the high-order lateral prefrontal cortex (LPFC) and the primary visual cortex (V1). Here, we used patch-clamp recordings and confocal and electron microscopy to determine whether these distinct synaptic responses are due to differences in firing rates of presynaptic neurons and/or in the features of presynaptic or postsynaptic entities. As with spontaneous EPSCs, TTX-insensitive (action potential-independent) miniature EPSCs exhibited significantly higher frequency, greater amplitude, and slower kinetics in LPFC compared with V1 neurons. Consistent with these physiological differences, LPFC neurons possessed higher densities of spines, and the mean width of large spines was greater compared with those on V1 neurons. Axospinous synapses in layers 2-3 of LPFC had larger postsynaptic density surface areas and a higher proportion of large perforated synapses compared with V1. Axonal boutons in LPFC were also larger in volume and contained ∼ 1.6× more vesicles than did those in V1. Further, LPFC had a higher density of AMPA GluR2 receptor labeling than V1. The properties of spines and synaptic currents of individual layer 3 pyramidal neurons measured here were significantly correlated, consistent with the idea that significantly more frequent and larger synaptic currents are likely due to more numerous, larger, and more powerful synapses in LPFC compared with V1.
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43
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Mighdoll MI, Tao R, Kleinman JE, Hyde TM. Myelin, myelin-related disorders, and psychosis. Schizophr Res 2015; 161:85-93. [PMID: 25449713 DOI: 10.1016/j.schres.2014.09.040] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/18/2014] [Accepted: 09/21/2014] [Indexed: 12/14/2022]
Abstract
The neuropathological basis of schizophrenia and related psychoses remains elusive despite intensive scientific investigation. Symptoms of psychosis have been reported in a number of conditions where normal myelin development is interrupted. The nature, location, and timing of white matter pathology seem to be key factors in the development of psychosis, especially during the critical adolescent period of association area myelination. Numerous lines of evidence implicate myelin and oligodendrocyte function as critical processes that could affect neuronal connectivity, which has been implicated as a central abnormality in schizophrenia. Phenocopies of schizophrenia with a known pathological basis involving demyelination or dysmyelination may offer insights into the biology of schizophrenia itself. This article reviews the pathological changes in white matter of patients with schizophrenia, as well as demyelinating diseases associated with psychosis. In an attempt to understand the potential role of dysmyelination in schizophrenia, we outline the evidence from a number of both clinically-based and post-mortem studies that provide evidence that OMR genes are genetically associated with increased risk for schizophrenia. To further understand the implication of white matter dysfunction and dysmyelination in schizophrenia, we examine diffusion tensor imaging (DTI), which has shown volumetric and microstructural white matter differences in patients with schizophrenia. While classical clinical-neuropathological correlations have established that disruption in myelination can produce a high fidelity phenocopy of psychosis similar to schizophrenia, the role of dysmyelination in schizophrenia remains controversial.
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Affiliation(s)
- Michelle I Mighdoll
- Lieber Institute for Brain Development, Johns Hopkins Medical Institutions, 855 N. Wolfe Street, Suite 300, Baltimore, MD 21205, USA.
| | - Ran Tao
- Lieber Institute for Brain Development, Johns Hopkins Medical Institutions, 855 N. Wolfe Street, Suite 300, Baltimore, MD 21205, USA.
| | - Joel E Kleinman
- Lieber Institute for Brain Development, Johns Hopkins Medical Institutions, 855 N. Wolfe Street, Suite 300, Baltimore, MD 21205, USA.
| | - Thomas M Hyde
- Lieber Institute for Brain Development, Johns Hopkins Medical Institutions, 855 N. Wolfe Street, Suite 300, Baltimore, MD 21205, USA; Department of Psychiatry & Behavioral Sciences, Johns Hopkins Medical School, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins Medical School, Baltimore, MD 21205, USA.
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44
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Csete G, Bognár A, Csibri P, Kaposvári P, Sáry G. Aging alters visual processing of objects and shapes in inferotemporal cortex in monkeys. Brain Res Bull 2014; 110:76-83. [PMID: 25526896 DOI: 10.1016/j.brainresbull.2014.11.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 11/21/2014] [Accepted: 11/22/2014] [Indexed: 12/14/2022]
Abstract
Visual perception declines with age. Perceptual deficits may originate not only in the optical system serving vision but also in the neural machinery processing visual information. Since homologies between monkey and human vision permit extrapolation from monkeys to humans, data from young, middle aged and old monkeys were analyzed to show age-related changes in the neuronal activity in the inferotemporal cortex, which is critical for object and shape vision. We found an increased neuronal response latency, and a decrease in the stimulus selectivity in the older animals and suggest that these changes may underlie the perceptual uncertainties found frequently in the elderly.
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Affiliation(s)
- G Csete
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary; Department of Neurology, Faculty of Medicine, Semmelweis u. 6, H-6725 Szeged, Hungary.
| | - A Bognár
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
| | - P Csibri
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
| | - P Kaposvári
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
| | - Gy Sáry
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
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45
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Zhan X, Jickling GC, Ander BP, Liu D, Stamova B, Cox C, Jin LW, DeCarli C, Sharp FR. Myelin injury and degraded myelin vesicles in Alzheimer's disease. Curr Alzheimer Res 2014; 11:232-8. [PMID: 24484278 DOI: 10.2174/1567205011666140131120922] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 11/22/2013] [Accepted: 11/25/2013] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Myelin disruption is an important feature of Alzheimer's disease (AD) that contributes to impairment of neuronal circuitry and cognition. In this study we characterize myelin degradation in the brains of patients with Alzheimer's disease compared with normal aged controls. METHODS Myelin from patients with AD (n=13) was compared to matched controls (n=6). Myelin degradation was examined by immunohistochemistry in frontal white matter (WM) for intact myelin basic protein (MBP), degraded MBP, the presence of myelin lipid and for PAS staining. The relationship of myelin degradation and axonal injury was also assessed. RESULTS Brains from patients with AD had significant loss of intact MBP, and an increase in degraded MBP in periventricular WM adjacent to a denuded ependymal layer. In regions of myelin degradation, vesicles were identified that stained positive for degraded MBP, myelin lipid, and neurofilament but not for intact MBP. Most vesicles stained for PAS, a corpora amylacea marker. The vesicles were significantly more abundant in the periventricular WM of AD patients compared to controls (44.5 ± 11.0 versus 1.7 ± 1.1, p=0.02). CONCLUSION In AD patients degraded MBP is associated in part with vesicles particularly in periventricular WM that is adjacent to areas of ependymal injury.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Frank R Sharp
- University of California at Davis, M.I.N.D. Institute - Room 2415, 2805 50th Street, Sacramento, CA 95817, USA.
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Lu PH, Lee GJ, Shapira J, Jimenez E, Mather MJ, Thompson PM, Bartzokis G, Mendez MF. Regional differences in white matter breakdown between frontotemporal dementia and early-onset Alzheimer's disease. J Alzheimers Dis 2014; 39:261-9. [PMID: 24150110 DOI: 10.3233/jad-131481] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND White matter abnormalities have been associated with both behavioral variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD). OBJECTIVE Using MRI diffusion tensor imaging (DTI) measures, we compared white matter integrity between patients with bvFTD and those with early-onset AD and correlated these biomarkers with behavioral symptoms involving emotional blunting. METHODS We studied 8 bvFTD and 12 AD patients as well as 12 demographically-matched healthy controls (NCs). Using four DTI metrics (fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity), we assessed the frontal lobes (FWM) and genu of the corpus callosum (GWM), which are vulnerable late-myelinating regions, and a contrasting early-myelinating region (splenium of the corpus callosum). The Scale for Emotional Blunting Scale (SEB) was used to assess emotional functioning of the study participants. RESULTS Compared to AD patients and NCs, the bvFTD subjects exhibited significantly worse FWM and GWM integrity on all four DTI metrics sensitive to myelin and axonal integrity. In contrast, AD patients showed a numerical trend toward worse splenium of the corpus callosum integrity than bvFTD and NC groups. Significant associations between SEB ratings and GWM DTI measures were demonstrated in the combined bvFTD and AD sample. When examined separately, these relationships remained robust for the bvFTD group but not the AD group. CONCLUSIONS The regional DTI alterations suggest that FTD and AD are each associated with a characteristic distribution of white matter degradation. White matter breakdown in late-myelinating regions was associated with symptoms of emotional blunting, particularly within the bvFTD group.
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Affiliation(s)
- Po H Lu
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Grace J Lee
- Department of Psychology, School of Behavioral Health, Loma Linda University, Loma Linda, CA, USA
| | - Jill Shapira
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA Greater Los Angeles VA Healthcare System, West Los Angeles, CA, USA
| | - Elvira Jimenez
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA Greater Los Angeles VA Healthcare System, West Los Angeles, CA, USA
| | | | - Paul M Thompson
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA Laboratory of Neuroimaging, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - George Bartzokis
- Laboratory of Neuroimaging, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Mario F Mendez
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA Greater Los Angeles VA Healthcare System, West Los Angeles, CA, USA
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47
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Are there roles for brain cell senescence in aging and neurodegenerative disorders? Biogerontology 2014; 15:643-60. [PMID: 25305051 DOI: 10.1007/s10522-014-9532-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 09/13/2014] [Indexed: 12/30/2022]
Abstract
The term cellular senescence was introduced more than five decades ago to describe the state of growth arrest observed in aging cells. Since this initial discovery, the phenotypes associated with cellular senescence have expanded beyond growth arrest to include alterations in cellular metabolism, secreted cytokines, epigenetic regulation and protein expression. Recently, senescence has been shown to play an important role in vivo not only in relation to aging, but also during embryonic development. Thus, cellular senescence serves different purposes and comprises a wide range of distinct phenotypes across multiple cell types. Whether all cell types, including post-mitotic neurons, are capable of entering into a senescent state remains unclear. In this review we examine recent data that suggest that cellular senescence plays a role in brain aging and, notably, may not be limited to glia but also neurons. We suggest that there is a high level of similarity between some of the pathological changes that occur in the brain in Alzheimer's and Parkinson's diseases and those phenotypes observed in cellular senescence, leading us to propose that neurons and glia can exhibit hallmarks of senescence previously documented in peripheral tissues.
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48
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Yuan N, Liang Z, Yang Y, Li G, Zhou Y. Changes of spatial and temporal frequency tuning properties of neurons in the middle temporal area of aged rhesus monkeys. Eur J Neurosci 2014; 40:2652-61. [PMID: 24888415 DOI: 10.1111/ejn.12634] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 04/11/2014] [Accepted: 04/25/2014] [Indexed: 11/30/2022]
Abstract
Aged humans exhibit severe deficits in visual motion perception and contrast sensitivity under various levels of spatial and temporal modulation. Previous studies indicated that many of these deficits are probably mediated by the neural degradation of the central visual system. To clarify the neuronal response mechanisms underlying the visual degradation during aging, we examined the spatial and temporal frequency tuning properties of neurons from anesthetised and paralysed aged monkeys at the middle temporal area (area MT), which is downstream of the primary visual cortex in the visual processing pathway and thought to be critical for motion perception. We found that the preferred spatial and temporal frequencies, spatial resolution and high temporal frequency cutoff of area MT neurons were reduced in aged monkeys, and were accompanied by the broadened tuning width of spatial frequency, elevated spontaneous activity, and decreased signal-to-noise ratio. These results showed that, for neurons in area MT, aging significantly changed both the spatial and temporal frequency response tuning properties. Such evidence provides new insight into the changes occurring at the electrophysiological level that may be related to the aging-related visual deficits, especially in processing spatial and temporal information.
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Affiliation(s)
- Nini Yuan
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China
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49
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Young ME, Ohm DT, Dumitriu D, Rapp PR, Morrison JH. Differential effects of aging on dendritic spines in visual cortex and prefrontal cortex of the rhesus monkey. Neuroscience 2014; 274:33-43. [PMID: 24853052 DOI: 10.1016/j.neuroscience.2014.05.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 04/22/2014] [Accepted: 05/02/2014] [Indexed: 01/11/2023]
Abstract
Aging decreases the density of spines and the proportion of thin spines in the non-human primate (NHP) dorsolateral prefrontal cortex (dlPFC). In this study, we used confocal imaging of dye-loaded neurons to expand upon previous results regarding the effects of aging on spine density and morphology in the NHP dlPFC and compared these results to the effects of aging on pyramidal neurons in the primary visual cortex (V1). We confirmed that spine density, and particularly the density of thin spines, decreased with age in the dlPFC of rhesus monkeys. Furthermore, the average head diameter of non-stubby spines in the dlPFC was a better predictor than chronological age of the number of trials required to reach criterion on both the delayed response test of visuospatial working memory and the delayed nonmatching-to-sample test of recognition memory. By contrast, total spine density was lower on neurons in V1 than in dlPFC, and neither total spine density, thin spine density, nor spine size in V1 was affected by aging. Our results highlight the importance and selective vulnerability of dlPFC thin spines for optimal prefrontal-mediated cognitive function. Understanding the nature of the selective vulnerability of dlPFC thin spines as compared to the resilience of thin spines in V1 may be a promising area of research in the quest to prevent or ameliorate age-related cognitive decline.
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Affiliation(s)
- M E Young
- Fishberg Department of Neuroscience, The Friedman Brain Institute, Kastor Neurobiology of Aging Laboratory, and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - D T Ohm
- Fishberg Department of Neuroscience, The Friedman Brain Institute, Kastor Neurobiology of Aging Laboratory, and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - D Dumitriu
- Fishberg Department of Neuroscience, The Friedman Brain Institute, Kastor Neurobiology of Aging Laboratory, and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - P R Rapp
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, MD 21224, USA
| | - J H Morrison
- Fishberg Department of Neuroscience, The Friedman Brain Institute, Kastor Neurobiology of Aging Laboratory, and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Geriatrics and Palliative Care, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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50
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Early structural and functional defects in synapses and myelinated axons in stratum lacunosum moleculare in two preclinical models for tauopathy. PLoS One 2014; 9:e87605. [PMID: 24498342 PMCID: PMC3912020 DOI: 10.1371/journal.pone.0087605] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/21/2013] [Indexed: 02/04/2023] Open
Abstract
The stratum lacunosum moleculare (SLM) is the connection hub between entorhinal cortex and hippocampus, two brain regions that are most vulnerable in Alzheimer's disease. We recently identified a specific synaptic deficit of Nectin-3 in transgenic models for tauopathy. Here we defined cognitive impairment and electrophysiological problems in the SLM of Tau.P301L mice, which corroborated the structural defects in synapses and dendritic spines. Reduced diffusion of DiI from the ERC to the hippocampus indicated defective myelinated axonal pathways. Ultrastructurally, myelinated axons in the temporoammonic pathway (TA) that connects ERC to CA1 were damaged in Tau.P301L mice at young age. Unexpectedly, the myelin defects were even more severe in bigenic biGT mice that co-express GSK3β with Tau.P301L in neurons. Combined, our data demonstrate that neuronal expression of protein Tau profoundly affected the functional and structural organization of the entorhinal-hippocampal complex, in particular synapses and myelinated axons in the SLM. White matter pathology deserves further attention in patients suffering from tauopathy and Alzheimer's disease.
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