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Dong J, Zhu XN, Zeng PM, Cao DD, Yang Y, Hu J, Luo ZG. A hominoid-specific signaling axis regulating the tempo of synaptic maturation. Cell Rep 2024; 43:114548. [PMID: 39052482 DOI: 10.1016/j.celrep.2024.114548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 04/15/2024] [Accepted: 07/12/2024] [Indexed: 07/27/2024] Open
Abstract
Human cortical neurons (hCNs) exhibit high dendritic complexity and synaptic density, and the maturation process is greatly protracted. However, the molecular mechanism governing these specific features remains unclear. Here, we report that the hominoid-specific gene TBC1D3 promotes dendritic arborization and protracts the pace of synaptogenesis. Ablation of TBC1D3 in induced hCNs causes reduction of dendritic growth and precocious synaptic maturation. Forced expression of TBC1D3 in the mouse cortex protracts synaptic maturation while increasing dendritic growth. Mechanistically, TBC1D3 functions via interaction with MICAL1, a monooxygenase that mediates oxidation of actin filament. At the early stage of differentiation, the TBC1D3/MICAL1 interaction in the cytosol promotes dendritic growth via F-actin oxidation and enhanced actin dynamics. At late stages, TBC1D3 escorts MICAL1 into the nucleus and downregulates the expression of genes related with synaptic maturation through interaction with the chromatin remodeling factor ATRX. Thus, this study delineates the molecular mechanisms underlying human neuron development.
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Affiliation(s)
- Jian Dong
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai 201210, China
| | - Xiao-Na Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Peng-Ming Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai 201210, China
| | - Dong-Dong Cao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai 201210, China
| | - Yang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai 201210, China
| | - Ji Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhen-Ge Luo
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai 201210, China.
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Miller PA, Williams-Ikhenoba JG, Sankhe AS, Hoffe BH, Chee MJ. Neuroanatomical, electrophysiological, and morphological characterization of melanin-concentrating hormone cells coexpressing cocaine- and amphetamine-regulated transcript. J Comp Neurol 2024; 532:e25588. [PMID: 38335050 DOI: 10.1002/cne.25588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 12/18/2023] [Accepted: 01/09/2024] [Indexed: 02/12/2024]
Abstract
Melanin-concentrating hormone (MCH) cells in the hypothalamus regulate fundamental physiological functions like energy balance, sleep, and reproduction. This diversity may be ascribed to the neurochemical heterogeneity among MCH cells. One prominent subpopulation of MCH cells coexpresses cocaine- and amphetamine-regulated transcript (CART), and as MCH and CART can have opposing actions, MCH/CART+ and MCH/CART- cells may differentially modulate behavioral outcomes. However, it is not known if there are differences in the cellular properties underlying their functional differences; thus, we compared the neuroanatomical, electrophysiological, and morphological properties of MCH cells in male and female Mch-cre;L10-Egfp reporter mice. Half of MCH cells expressed CART and were most prominent in the medial hypothalamus. Whole-cell patch-clamp recordings revealed differences in their passive and active membrane properties in a sex-dependent manner. Female MCH/CART+ cells had lower input resistances, but male cells largely differed in their firing properties. All MCH cells increased firing when stimulated, but their firing frequency decreases with sustained stimulation. MCH/CART+ cells showed stronger spike rate adaptation than MCH/CART- cells. The kinetics of excitatory events at MCH cells also differed by cell type, as the rising rate of excitatory events was slower at MCH/CART+ cells. By reconstructing the dendritic arborization of our recorded cells, we found no sex differences, but male MCH/CART+ cells had less dendritic length and fewer branch points. Overall, distinctions in topographical division and cellular properties between MCH cells add to their heterogeneity and help elucidate their response to stimuli or effect on modulating their respective neural networks.
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Affiliation(s)
| | | | - Aditi S Sankhe
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Brendan H Hoffe
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Melissa J Chee
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
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3
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Cangalaya C, Wegmann S, Sun W, Diez L, Gottfried A, Richter K, Stoyanov S, Pakan J, Fischer KD, Dityatev A. Real-time mechanisms of exacerbated synaptic remodeling by microglia in acute models of systemic inflammation and tauopathy. Brain Behav Immun 2023; 110:245-259. [PMID: 36906076 DOI: 10.1016/j.bbi.2023.02.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/13/2023] Open
Abstract
Remodeling of synapses by microglia is essential for synaptic plasticity in the brain. However, during neuroinflammation and neurodegenerative diseases, microglia can induce excessive synaptic loss, although the precise underlying mechanisms are unknown. To directly observe microglia-synapse interactions under inflammatory conditions, we performed in vivo two-photon time-lapse imaging of microglia-synapse interactions after bacterial lipopolysaccharide administration to model systemic inflammation, or after inoculation of Alzheimer's disease (AD) brain extracts to model disease-associated neuroinflammatory microglial response. Both treatments prolonged microglia-neuron contacts, decreased basal surveillance of synapses and promoted synaptic remodeling in response to synaptic stress induced by focal single-synapse photodamage. Spine elimination correlated with the expression of microglial complement system/phagocytic proteins and the occurrence of synaptic filopodia. Microglia were observed contacting spines, then stretching and phagocytosing spine head filopodia. Thus, in response to inflammatory stimuli microglia exacerbated spine remodeling through prolonged microglial contact and elimination of spines 'tagged' by synaptic filopodia.
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Affiliation(s)
- Carla Cangalaya
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany; Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Magdeburg, Germany; ESF International Graduate School on Analysis, Imaging and Modelling of Neuronal and Inflammatory Processes, Magdeburg, Germany
| | - Susanne Wegmann
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Weilun Sun
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Lisa Diez
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Anna Gottfried
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Magdeburg, Germany
| | - Karin Richter
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Magdeburg, Germany
| | - Stoyan Stoyanov
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Janelle Pakan
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany; Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Klaus-Dieter Fischer
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical Faculty, Magdeburg, Germany
| | - Alexander Dityatev
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany; Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.
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4
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Zaccard CR, Gippo I, Song A, Geula C, Penzes P. Dendritic spinule-mediated structural synaptic plasticity: Implications for development, aging, and psychiatric disease. Front Mol Neurosci 2023; 16:1059730. [PMID: 36741924 PMCID: PMC9895827 DOI: 10.3389/fnmol.2023.1059730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 01/04/2023] [Indexed: 01/22/2023] Open
Abstract
Dendritic spines are highly dynamic and changes in their density, size, and shape underlie structural synaptic plasticity in cognition and memory. Fine membranous protrusions of spines, termed dendritic spinules, can contact neighboring neurons or glial cells and are positively regulated by neuronal activity. Spinules are thinner than filopodia, variable in length, and often emerge from large mushroom spines. Due to their nanoscale, spinules have frequently been overlooked in diffraction-limited microscopy datasets. Until recently, our knowledge of spinules has been interpreted largely from single snapshots in time captured by electron microscopy. We summarize herein the current knowledge about the molecular mechanisms of spinule formation. Additionally, we discuss possible spinule functions in structural synaptic plasticity in the context of development, adulthood, aging, and psychiatric disorders. The literature collectively implicates spinules as a mode of structural synaptic plasticity and suggests the existence of morphologically and functionally distinct spinule subsets. A recent time-lapse, enhanced resolution imaging study demonstrated that the majority of spinules are small, short-lived, and dynamic, potentially exploring their environment or mediating retrograde signaling and membrane remodeling via trans-endocytosis. A subset of activity-enhanced, elongated, long-lived spinules is associated with complex PSDs, and preferentially contacts adjacent axonal boutons not presynaptic to the spine head. Hence, long-lived spinules can form secondary synapses with the potential to alter synaptic connectivity. Published studies further suggest that decreased spinules are associated with impaired synaptic plasticity and intellectual disability, while increased spinules are linked to hyperexcitability and neurodegenerative diseases. In summary, the literature indicates that spinules mediate structural synaptic plasticity and perturbations in spinules can contribute to synaptic dysfunction and psychiatric disease. Additional studies would be beneficial to further delineate the molecular mechanisms of spinule formation and determine the exact role of spinules in development, adulthood, aging, and psychiatric disorders.
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Affiliation(s)
- Colleen R. Zaccard
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Isabel Gippo
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Amy Song
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Changiz Geula
- Mesulam Center for Cognitive Neurology and Alzheimer's Disease, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Peter Penzes
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, United States,Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States,*Correspondence: Peter Penzes,
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Jorratt P, Ricny J, Leibold C, Ovsepian SV. Endogenous Modulators of NMDA Receptor Control Dendritic Field Expansion of Cortical Neurons. Mol Neurobiol 2023; 60:1440-1452. [PMID: 36462136 PMCID: PMC9899188 DOI: 10.1007/s12035-022-03147-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022]
Abstract
Impairments of N-methyl-D-aspartate receptor (NMDAR) activity have been implicated in several neuropsychiatric disorders, with pharmacological inhibition of NMDAR-mediated currents and associated neurobehavioral changes considered as a model of schizophrenia. We analyzed the effects of brief and long-term exposure of rat cortical cultures to the most prevalent endogenous modulators of NMDAR (kynurenic acid, pregnenolone sulfate, spermidine, and zinc) on neuronal viability, stimulation-induced release of glutamate, and dendritic morphology with synaptic density. Both, glutamate release and neuronal viability studies revealed no difference between the test and control groups. No differences were also observed in the number of dendritic branching and length, or density of synaptic connections and neuronal soma size. Comparison of the extent of dendritic projections and branching patterns, however, revealed enhanced distal arborization with the expansion of the dendritic area under prolonged treatment of cultures with physiological concentrations of NMDAR modulators, with differences reaching significance in spermidine and pregnenolone sulfate tests. Measurements of the density of glutamatergic synapses showed consistency across all neuronal groups, except those treated with pregnenolone sulfate, which showed a reduction of PSD-95-positive elements. Overall, our data suggest that constitutive glutamatergic activity mediated by NMDAR controls the dendritic field expansion and can influence the integrative properties of cortical neurons.
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Affiliation(s)
- Pascal Jorratt
- grid.447902.cNational Institute of Mental Health, Klecany, Czech Republic ,grid.4491.80000 0004 1937 116XThird Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jan Ricny
- grid.447902.cNational Institute of Mental Health, Klecany, Czech Republic
| | - Christian Leibold
- grid.5963.9Faculty of Biology and Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Saak V. Ovsepian
- grid.36316.310000 0001 0806 5472Faculty of Science and Engineering, University of Greenwich London, Chatham Maritime, Kent, ME4 4TB UK
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KASAI H. Unraveling the mysteries of dendritic spine dynamics: Five key principles shaping memory and cognition. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2023; 99:254-305. [PMID: 37821392 PMCID: PMC10749395 DOI: 10.2183/pjab.99.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 07/11/2023] [Indexed: 10/13/2023]
Abstract
Recent research extends our understanding of brain processes beyond just action potentials and chemical transmissions within neural circuits, emphasizing the mechanical forces generated by excitatory synapses on dendritic spines to modulate presynaptic function. From in vivo and in vitro studies, we outline five central principles of synaptic mechanics in brain function: P1: Stability - Underpinning the integral relationship between the structure and function of the spine synapses. P2: Extrinsic dynamics - Highlighting synapse-selective structural plasticity which plays a crucial role in Hebbian associative learning, distinct from pathway-selective long-term potentiation (LTP) and depression (LTD). P3: Neuromodulation - Analyzing the role of G-protein-coupled receptors, particularly dopamine receptors, in time-sensitive modulation of associative learning frameworks such as Pavlovian classical conditioning and Thorndike's reinforcement learning (RL). P4: Instability - Addressing the intrinsic dynamics crucial to memory management during continual learning, spotlighting their role in "spine dysgenesis" associated with mental disorders. P5: Mechanics - Exploring how synaptic mechanics influence both sides of synapses to establish structural traces of short- and long-term memory, thereby aiding the integration of mental functions. We also delve into the historical background and foresee impending challenges.
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Affiliation(s)
- Haruo KASAI
- International Research Center for Neurointelligence (WPI-IRCN), UTIAS, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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7
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Heck N, Santos MD. Dendritic Spines in Learning and Memory: From First Discoveries to Current Insights. ADVANCES IN NEUROBIOLOGY 2023; 34:311-348. [PMID: 37962799 DOI: 10.1007/978-3-031-36159-3_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The central nervous system is composed of neural ensembles, and their activity patterns are neural correlates of cognitive functions. Those ensembles are networks of neurons connected to each other by synapses. Most neurons integrate synaptic signal through a remarkable subcellular structure called spine. Dendritic spines are protrusions whose diverse shapes make them appear as a specific neuronal compartment, and they have been the focus of studies for more than a century. Soon after their first description by Ramón y Cajal, it has been hypothesized that spine morphological changes could modify neuronal connectivity and sustain cognitive abilities. Later studies demonstrated that changes in spine density and morphology occurred in experience-dependent plasticity during development, and in clinical cases of mental retardation. This gave ground for the assumption that dendritic spines are the particular locus of cerebral plasticity. With the discovery of synaptic long-term potentiation, a research program emerged with the aim to establish whether dendritic spine plasticity could explain learning and memory. The development of live imaging methods revealed on the one hand that dendritic spine remodeling is compatible with learning process and, on the other hand, that their long-term stability is compatible with lifelong memories. Furthermore, the study of the mechanisms of spine growth and maintenance shed new light on the rules of plasticity. In behavioral paradigms of memory, spine formation or elimination and morphological changes were found to correlate with learning. In a last critical step, recent experiments have provided evidence that dendritic spines play a causal role in learning and memory.
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Affiliation(s)
- Nicolas Heck
- Laboratory Neurosciences Paris Seine, Sorbonne Université, Paris, France.
| | - Marc Dos Santos
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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3dSpAn: An interactive software for 3D segmentation and analysis of dendritic spines. Neuroinformatics 2022; 20:679-698. [PMID: 34743262 DOI: 10.1007/s12021-021-09549-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2021] [Indexed: 12/31/2022]
Abstract
Three-dimensional segmentation and analysis of dendritic spine morphology involve two major challenges: 1) how to segment individual spines from the dendrites and 2) how to quantitatively assess the morphology of individual spines. To address these two issues, we developed software called 3dSpAn (3-dimensional Spine Analysis), based on implementing a previously published method, 3D multi-scale opening algorithm in shared intensity space. 3dSpAn consists of four modules: a) Preprocessing and Region of Interest (ROI) selection, b) Intensity thresholding and seed selection, c) Multi-scale segmentation, and d) Quantitative morphological feature extraction. In this article, we present the results of segmentation and morphological analysis for different observation methods and conditions, including in vitro and ex vivo imaging with confocal microscopy, and in vivo observations using high-resolution two-photon microscopy. In particular, we focus on software usage, the influence of adjustable parameters on the obtained results, user reproducibility, accuracy analysis, and also include a qualitative comparison with a commercial benchmark. 3dSpAn software is freely available for non-commercial use at www.3dSpAn.org .
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Vergara P, Pino G, Vera J, Arancibia F, Sanhueza M. Heterogeneous CaMKII-Dependent Synaptic Compensations in CA1 Pyramidal Neurons From Acute Hippocampal Slices. Front Cell Neurosci 2022; 16:821088. [PMID: 35431809 PMCID: PMC9005847 DOI: 10.3389/fncel.2022.821088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Prolonged changes in neural activity trigger homeostatic synaptic plasticity (HSP) allowing neuronal networks to operate within functional ranges. Cell-wide or input-specific adaptations can be induced by pharmacological or genetic manipulations of activity, and by sensory deprivation. Reactive functional changes caused by deafferentation may partially share mechanisms with HSP. Acute hippocampal slices are a suitable model to investigate relatively rapid (hours) modifications occurring after denervation and explore the underlying mechanisms. As during slicing many afferents are cut, we conducted whole-cell recordings of miniature excitatory postsynaptic currents (mEPSCs) in CA1 pyramidal neurons to evaluate changes over the following 12 h. As Schaffer collaterals constitute a major glutamatergic input to these neurons, we also dissected CA3. We observed an average increment in mEPSCs amplitude and a decrease in decay time, suggesting synaptic AMPA receptor upregulation and subunit content modifications. Sorting mEPSC by rise time, a correlate of synapse location along dendrites, revealed amplitude raises at two separate domains. A specific frequency increase was observed in the same domains and was accompanied by a global, unspecific raise. Amplitude and frequency increments were lower at sites initially more active, consistent with local compensatory processes. Transient preincubation with a specific Ca2+/calmodulin-dependent kinase II (CaMKII) inhibitor either blocked or occluded amplitude and frequency upregulation in different synapse populations. Results are consistent with the concurrent development of different known CaMKII-dependent HSP processes. Our observations support that deafferentation causes rapid and diverse compensations resembling classical slow forms of adaptation to inactivity. These results may contribute to understand fast-developing homeostatic or pathological events after brain injury.
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Cheng J, Fairchild JK, McNerney MW, Noda A, Ashford JW, Suppes T, Chao SZ, Taylor J, Rosen AC, Durazzo TC, Lazzeroni LC, Yesavage J. Repetitive Transcranial Magnetic Stimulation as a Treatment for Veterans with Cognitive Impairment and Multiple Comorbidities. J Alzheimers Dis 2022; 85:1593-1600. [PMID: 34958013 PMCID: PMC10629368 DOI: 10.3233/jad-210349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Despite decades of research efforts, current treatments for Alzheimer's disease (AD) are of limited effectiveness and do not halt the progression of the disease and associated cognitive decline. Studies have shown that repetitive transcranial magnetic stimulation (rTMS) may improve cognition. OBJECTIVE We conducted a pilot study to investigate the effect of rTMS on cognitive function in Veterans with numerous medical comorbidities. METHODS Participants underwent 20 sessions, over the course of approximately 4 weeks, of 10 Hz rTMS at the left dorsolateral prefrontal cortex with intensity of 120% resting motor threshold. Outcome measures including memory, language, verbal fluency, and executive functions were acquired at baseline, end of treatment, and 4 months after the last rTMS session. Twenty-six Veterans completed the study (13 in the active rTMS group, 13 in the sham rTMS group). RESULTS The study protocol was well-tolerated. Active, compared to sham, rTMS showed improved auditory-verbal memory at the end of treatment and at 4-month follow-up. However, the active rTMS group demonstrated a trend in decreased semantic verbal fluency at the end of treatment and at 4-month follow up. CONCLUSION These preliminary results show rTMS is safe in general in this elderly Veteran population with multiple co-morbidities. Patients in the sham group showed an expected, slight decline in the California Verbal Learning Test scores over the course of the study, whereas the active treatment group showed a slight improvement at the 4-month post-treatment follow up. These effects need to be confirmed by studies of larger sample sizes.
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Affiliation(s)
- Jauhtai Cheng
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - J Kaci Fairchild
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - M Windy McNerney
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Art Noda
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - J Wesson Ashford
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Trisha Suppes
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Steven Z Chao
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Neurology and Neurological Science, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Joy Taylor
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Allyson C Rosen
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Timothy C Durazzo
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Laura C Lazzeroni
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Jerome Yesavage
- VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
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11
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Wildenberg G, Sorokina A, Koranda J, Monical A, Heer C, Sheffield M, Zhuang X, McGehee D, Kasthuri B. Partial connectomes of labeled dopaminergic circuits reveal non-synaptic communication and axonal remodeling after exposure to cocaine. eLife 2021; 10:71981. [PMID: 34965204 PMCID: PMC8716107 DOI: 10.7554/elife.71981] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 11/29/2021] [Indexed: 12/15/2022] Open
Abstract
Dopaminergic (DA) neurons exert profound influences on behavior including addiction. However, how DA axons communicate with target neurons and how those communications change with drug exposure remains poorly understood. We leverage cell type-specific labeling with large volume serial electron microscopy to detail DA connections in the nucleus accumbens (NAc) of the mouse (Mus musculus) before and after exposure to cocaine. We find that individual DA axons contain different varicosity types based on their vesicle contents. Spatially ordering along individual axons further suggests that varicosity types are non-randomly organized. DA axon varicosities rarely make specific synapses (<2%, 6/410), but instead are more likely to form spinule-like structures (15%, 61/410) with neighboring neurons. Days after a brief exposure to cocaine, DA axons were extensively branched relative to controls, formed blind-ended 'bulbs' filled with mitochondria, and were surrounded by elaborated glia. Finally, mitochondrial lengths increased by ~2.2 times relative to control only in DA axons and NAc spiny dendrites after cocaine exposure. We conclude that DA axonal transmission is unlikely to be mediated via classical synapses in the NAc and that the major locus of anatomical plasticity of DA circuits after exposure to cocaine are large-scale axonal re-arrangements with correlated changes in mitochondria.
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Affiliation(s)
- Gregg Wildenberg
- Department of Neurobiology, University of Chicago, Chicago, United States.,Argonne National Laboratory, Lemont, United States
| | - Anastasia Sorokina
- Department of Neurobiology, University of Chicago, Chicago, United States.,Argonne National Laboratory, Lemont, United States
| | - Jessica Koranda
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Alexis Monical
- Department of Anesthesia & Critical Care, University of Chicago, Chicago, United States
| | - Chad Heer
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Mark Sheffield
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Xiaoxi Zhuang
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Daniel McGehee
- Department of Anesthesia & Critical Care, University of Chicago, Chicago, United States
| | - Bobby Kasthuri
- Department of Neurobiology, University of Chicago, Chicago, United States.,Argonne National Laboratory, Lemont, United States
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12
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Sleep promotes the formation of dendritic filopodia and spines near learning-inactive existing spines. Proc Natl Acad Sci U S A 2021; 118:2114856118. [PMID: 34873044 DOI: 10.1073/pnas.2114856118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2021] [Indexed: 01/20/2023] Open
Abstract
Changes in synaptic connections are believed to underlie long-term memory storage. Previous studies have suggested that sleep is important for synapse formation after learning, but how sleep is involved in the process of synapse formation remains unclear. To address this question, we used transcranial two-photon microscopy to investigate the effect of postlearning sleep on the location of newly formed dendritic filopodia and spines of layer 5 pyramidal neurons in the primary motor cortex of adolescent mice. We found that newly formed filopodia and spines were partially clustered with existing spines along individual dendritic segments 24 h after motor training. Notably, posttraining sleep was critical for promoting the formation of dendritic filopodia and spines clustered with existing spines within 8 h. A fraction of these filopodia was converted into new spines and contributed to clustered spine formation 24 h after motor training. This sleep-dependent spine formation via filopodia was different from retraining-induced new spine formation, which emerged from dendritic shafts without prior presence of filopodia. Furthermore, sleep-dependent new filopodia and spines tended to be formed away from existing spines that were active at the time of motor training. Taken together, these findings reveal a role of postlearning sleep in regulating the number and location of new synapses via promoting filopodial formation.
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Long-term effect of neonatal antagonism of ionotropic glutamate receptors on dendritic spines and cognitive function in rats. J Chem Neuroanat 2021; 119:102054. [PMID: 34839003 DOI: 10.1016/j.jchemneu.2021.102054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/04/2021] [Accepted: 11/23/2021] [Indexed: 12/11/2022]
Abstract
Glutamate is the most abundant excitatory neurotransmitter in the hippocampus where mediates its actions by activating glutamate receptors. The activation of these receptors is essential for the maintenance and dynamics of dendritic spines and plasticity that correlate with learning and memory processes during neurodevelopment and adulthood. We studied in adults the effect of blocking ionotropic glutamate receptors (NMDAR, AMPAR, and KAR) functions at neonatal age (PD1-PD15) with their respective antagonists D-AP5, GYKI-53655 and UBP-302. We first evaluated memory using a new object recognition test in adults. Second, we evaluated the levels of glial fibrillary acidic protein, synaptophysin and actin with immunohistochemistry in the CA1, CA3, and dentate gyrus regions of the hippocampus and, finally, the number of dendritic spines and their dynamics using Golgi-Cox staining. We found that ionotropic glutamate receptor function blockade at neonatal age causes a reduction in short and long-term memory in adulthood and a reduction in the expression of synaptophysin and actin protein levels in the hippocampus regions studied. This blockade also reduced the number of dendritic spines and modified dendritic dynamics in the CA1 region. The antagonism of the three types of ionotropic glutamate receptors reduced the mushrooms and bifurcated types of spines and increased the thin spines. The number of stubby spines was reduced by D-AP5, increased by UPB-302, and not affected by GYKI-53655. Our results indicate that the blockade of neonatal ionotropic glutamate receptors produces alterations that persist until adulthood.
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14
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Vallés AS, Barrantes FJ. Nanoscale Sub-Compartmentalization of the Dendritic Spine Compartment. Biomolecules 2021; 11:1697. [PMID: 34827695 PMCID: PMC8615865 DOI: 10.3390/biom11111697] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 01/04/2023] Open
Abstract
Compartmentalization of the membrane is essential for cells to perform highly specific tasks and spatially constrained biochemical functions in topographically defined areas. These membrane lateral heterogeneities range from nanoscopic dimensions, often involving only a few molecular constituents, to micron-sized mesoscopic domains resulting from the coalescence of nanodomains. Short-lived domains lasting for a few milliseconds coexist with more stable platforms lasting from minutes to days. This panoply of lateral domains subserves the great variety of demands of cell physiology, particularly high for those implicated in signaling. The dendritic spine, a subcellular structure of neurons at the receiving (postsynaptic) end of central nervous system excitatory synapses, exploits this compartmentalization principle. In its most frequent adult morphology, the mushroom-shaped spine harbors neurotransmitter receptors, enzymes, and scaffolding proteins tightly packed in a volume of a few femtoliters. In addition to constituting a mesoscopic lateral heterogeneity of the dendritic arborization, the dendritic spine postsynaptic membrane is further compartmentalized into spatially delimited nanodomains that execute separate functions in the synapse. This review discusses the functional relevance of compartmentalization and nanodomain organization in synaptic transmission and plasticity and exemplifies the importance of this parcelization in various neurotransmitter signaling systems operating at dendritic spines, using two fast ligand-gated ionotropic receptors, the nicotinic acetylcholine receptor and the glutamatergic receptor, and a second-messenger G-protein coupled receptor, the cannabinoid receptor, as paradigmatic examples.
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Affiliation(s)
- Ana Sofía Vallés
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (UNS-CONICET), Bahía Blanca 8000, Argentina;
| | - Francisco J. Barrantes
- Laboratory of Molecular Neurobiology, Institute of Biomedical Research (BIOMED), UCA-CONICET, Av. Alicia Moreau de Justo 1600, Buenos Aires C1107AFF, Argentina
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15
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Vallés AS, Barrantes FJ. Dendritic spine membrane proteome and its alterations in autistic spectrum disorder. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 128:435-474. [PMID: 35034726 DOI: 10.1016/bs.apcsb.2021.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dendritic spines are small protrusions stemming from the dendritic shaft that constitute the primary specialization for receiving and processing excitatory neurotransmission in brain synapses. The disruption of dendritic spine function in several neurological and neuropsychiatric diseases leads to severe information-processing deficits with impairments in neuronal connectivity and plasticity. Spine dysregulation is usually accompanied by morphological alterations to spine shape, size and/or number that may occur at early pathophysiological stages and not necessarily be reflected in clinical manifestations. Autism spectrum disorder (ASD) is one such group of diseases involving changes in neuronal connectivity and abnormal morphology of dendritic spines on postsynaptic neurons. These alterations at the subcellular level correlate with molecular changes in the spine proteome, with alterations in the copy number, topography, or in severe cases in the phenotype of the molecular components, predominantly of those proteins involved in spine recognition and adhesion, reflected in abnormally short lifetimes of the synapse and compensatory increases in synaptic connections. Since cholinergic neurotransmission participates in the regulation of cognitive function (attention, memory, learning processes, cognitive flexibility, social interactions) brain acetylcholine receptors are likely to play an important role in the dysfunctional synapses in ASD, either directly or indirectly via the modulatory functions exerted on other neurotransmitter receptor proteins and spine-resident proteins.
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Affiliation(s)
- Ana Sofía Vallés
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (UNS-CONICET), Bahía Blanca, Argentina
| | - Francisco J Barrantes
- Instituto de Investigaciones Biomédicas (BIOMED), UCA-CONICET, Buenos Aires, Argentina.
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16
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Sinha A, Metzner C, Davey N, Adams R, Schmuker M, Steuber V. Growth rules for the repair of Asynchronous Irregular neuronal networks after peripheral lesions. PLoS Comput Biol 2021; 17:e1008996. [PMID: 34061830 PMCID: PMC8195387 DOI: 10.1371/journal.pcbi.1008996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/11/2021] [Accepted: 04/23/2021] [Indexed: 12/02/2022] Open
Abstract
Several homeostatic mechanisms enable the brain to maintain desired levels of neuronal activity. One of these, homeostatic structural plasticity, has been reported to restore activity in networks disrupted by peripheral lesions by altering their neuronal connectivity. While multiple lesion experiments have studied the changes in neurite morphology that underlie modifications of synapses in these networks, the underlying mechanisms that drive these changes are yet to be explained. Evidence suggests that neuronal activity modulates neurite morphology and may stimulate neurites to selective sprout or retract to restore network activity levels. We developed a new spiking network model of peripheral lesioning and accurately reproduced the characteristics of network repair after deafferentation that are reported in experiments to study the activity dependent growth regimes of neurites. To ensure that our simulations closely resemble the behaviour of networks in the brain, we model deafferentation in a biologically realistic balanced network model that exhibits low frequency Asynchronous Irregular (AI) activity as observed in cerebral cortex. Our simulation results indicate that the re-establishment of activity in neurons both within and outside the deprived region, the Lesion Projection Zone (LPZ), requires opposite activity dependent growth rules for excitatory and inhibitory post-synaptic elements. Analysis of these growth regimes indicates that they also contribute to the maintenance of activity levels in individual neurons. Furthermore, in our model, the directional formation of synapses that is observed in experiments requires that pre-synaptic excitatory and inhibitory elements also follow opposite growth rules. Lastly, we observe that our proposed structural plasticity growth rules and the inhibitory synaptic plasticity mechanism that also balances our AI network both contribute to the restoration of the network to pre-deafferentation stable activity levels. An accumulating body of evidence suggests that our brain can compensate for peripheral lesions by adaptive rewiring of its neuronal circuitry. The underlying process, structural plasticity, can modify the connectivity of neuronal networks in the brain, thus affecting their function. To better understand the mechanisms of structural plasticity in the brain, we have developed a novel model of peripheral lesions and the resulting activity-dependent rewiring in a simplified balanced cortical network model that exhibits biologically realistic Asynchronous Irregular (AI) activity. In order to accurately reproduce the directionality and course of network rewiring after injury that is observed in peripheral lesion experiments, we derive activity dependent growth rules for different synaptic elements: dendritic and axonal contacts. Our simulation results suggest that excitatory and inhibitory synaptic elements have to react to changes in neuronal activity in opposite ways. We show that these rules result in a homeostatic stabilisation of activity in individual neurons. In our simulations, both synaptic and structural plasticity mechanisms contribute to network repair. Furthermore, our simulations indicate that while activity is restored in neurons deprived by the peripheral lesion, the temporal firing characteristics of the network may not be retained by the rewiring process.
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Affiliation(s)
- Ankur Sinha
- UH Biocomputation Research Group, Centre for Computer Science and Informatics Research, University of Hertfordshire, Hatfield United Kingdom
- * E-mail:
| | - Christoph Metzner
- UH Biocomputation Research Group, Centre for Computer Science and Informatics Research, University of Hertfordshire, Hatfield United Kingdom
- Department of Software Engineering and Theoretical Computer Science, Technische Universität Berlin, Berlin, Germany
| | - Neil Davey
- UH Biocomputation Research Group, Centre for Computer Science and Informatics Research, University of Hertfordshire, Hatfield United Kingdom
| | - Roderick Adams
- UH Biocomputation Research Group, Centre for Computer Science and Informatics Research, University of Hertfordshire, Hatfield United Kingdom
| | - Michael Schmuker
- UH Biocomputation Research Group, Centre for Computer Science and Informatics Research, University of Hertfordshire, Hatfield United Kingdom
| | - Volker Steuber
- UH Biocomputation Research Group, Centre for Computer Science and Informatics Research, University of Hertfordshire, Hatfield United Kingdom
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17
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Bączyńska E, Pels KK, Basu S, Włodarczyk J, Ruszczycki B. Quantification of Dendritic Spines Remodeling under Physiological Stimuli and in Pathological Conditions. Int J Mol Sci 2021; 22:4053. [PMID: 33919977 PMCID: PMC8070910 DOI: 10.3390/ijms22084053] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 12/14/2022] Open
Abstract
Numerous brain diseases are associated with abnormalities in morphology and density of dendritic spines, small membranous protrusions whose structural geometry correlates with the strength of synaptic connections. Thus, the quantitative analysis of dendritic spines remodeling in microscopic images is one of the key elements towards understanding mechanisms of structural neuronal plasticity and bases of brain pathology. In the following article, we review experimental approaches designed to assess quantitative features of dendritic spines under physiological stimuli and in pathological conditions. We compare various methodological pipelines of biological models, sample preparation, data analysis, image acquisition, sample size, and statistical analysis. The methodology and results of relevant experiments are systematically summarized in a tabular form. In particular, we focus on quantitative data regarding the number of animals, cells, dendritic spines, types of studied parameters, size of observed changes, and their statistical significance.
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Affiliation(s)
- Ewa Bączyńska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland; (E.B.); (K.K.P.); (J.W.)
| | - Katarzyna Karolina Pels
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland; (E.B.); (K.K.P.); (J.W.)
| | - Subhadip Basu
- Department of Computer Science and Engineering, Jadvapur University, Kolkata 700032, India;
| | - Jakub Włodarczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland; (E.B.); (K.K.P.); (J.W.)
| | - Błażej Ruszczycki
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland; (E.B.); (K.K.P.); (J.W.)
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18
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Puig-Lagunes ÁA, Rocha L, Morgado-Valle C, BeltrÁn-Parrazal L, LÓpez-Meraz ML. Brain and plasma amino acid concentration in infant rats prenatally exposed to valproic acid. AN ACAD BRAS CIENC 2021; 93:e20190861. [PMID: 33729379 DOI: 10.1590/0001-3765202120190861] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 10/19/2019] [Indexed: 11/22/2022] Open
Abstract
Autism spectrum disorder is associated with alterations in GABAergic and glutamatergic neurotransmission. Here, we aimed to determine the concentration of GABA, glutamate, glutamine, aspartate, taurine, and glycine in brain tissue and plasma of rats prenatally exposed to valproic acid (VPA), a well-characterized experimental model of autism. Pregnant rats were injected with VPA (600mg/Kg) during the twelfth-embryonic-day. Control rats were injected with saline. On the fourteen-postnatal-day, rats from both groups (males and females) were anesthetized, euthanized by decapitation and their brain dissected out. The frontal cortex, hippocampus, amygdala, brain stem and cerebellum were dissected and homogenized. Homogenates were centrifuged and supernatants were used to quantify amino acid concentrations by HPLC coupled with fluorometric detection. Blood samples were obtained by a cardiac puncture; plasma was separated and deproteinized to quantify amino acid concentration by HPLC. We found that, in VPA rats, glutamate and glutamine concentrations were increased in hippocampus and glycine concentration was increased in cortex. We did not find changes in other regions or in plasma amino acid concentration in the VPA group with respect to control group. Our results suggest that VPA exposure in utero may impair inhibitory and excitatory amino acid transmission in the infant brain.
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Affiliation(s)
- Ángel Alberto Puig-Lagunes
- Centro de Investigaciones Cerebrales, Universidad Veracruzana, Médicos y Odontólogos, s/n, Col. Unidad del Bosque, 91010 Xalapa, Veracruz, México
| | - Luisa Rocha
- Departamento de Farmacobiología, Cinvestav, Calzada de los Tenorios, 235, 14330 Col. Granjas Coapa, Ciudad de México, México
| | - Consuelo Morgado-Valle
- Centro de Investigaciones Cerebrales, Universidad Veracruzana, Médicos y Odontólogos, s/n, Col. Unidad del Bosque, 91010 Xalapa, Veracruz, México
| | - Luis BeltrÁn-Parrazal
- Centro de Investigaciones Cerebrales, Universidad Veracruzana, Médicos y Odontólogos, s/n, Col. Unidad del Bosque, 91010 Xalapa, Veracruz, México
| | - MarÍa-Leonor LÓpez-Meraz
- Centro de Investigaciones Cerebrales, Universidad Veracruzana, Médicos y Odontólogos, s/n, Col. Unidad del Bosque, 91010 Xalapa, Veracruz, México
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19
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Kuhlmann N, Wagner Valladolid M, Quesada-Ramírez L, Farrer MJ, Milnerwood AJ. Chronic and Acute Manipulation of Cortical Glutamate Transmission Induces Structural and Synaptic Changes in Co-cultured Striatal Neurons. Front Cell Neurosci 2021; 15:569031. [PMID: 33679324 PMCID: PMC7930618 DOI: 10.3389/fncel.2021.569031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 01/26/2021] [Indexed: 12/13/2022] Open
Abstract
In contrast to the prenatal topographic development of sensory cortices, striatal circuit organization is slow and requires the functional maturation of cortical and thalamic excitatory inputs throughout the first postnatal month. While mechanisms regulating synapse development and plasticity are quite well described at excitatory synapses of glutamatergic neurons in the neocortex, comparatively little is known of how this translates to glutamate synapses onto GABAergic neurons in the striatum. Here we investigate excitatory striatal synapse plasticity in an in vitro system, where glutamate can be studied in isolation from dopamine and other neuromodulators. We examined pre-and post-synaptic structural and functional plasticity in GABAergic striatal spiny projection neurons (SPNs), co-cultured with glutamatergic cortical neurons. After synapse formation, medium-term (24 h) TTX silencing increased the density of filopodia, and modestly decreased dendritic spine density, when assayed at 21 days in vitro (DIV). Spine reductions appeared to require residual spontaneous activation of ionotropic glutamate receptors. Conversely, chronic (14 days) TTX silencing markedly reduced spine density without any observed increase in filopodia density. Time-dependent, biphasic changes to the presynaptic marker Synapsin-1 were also observed, independent of residual spontaneous activity. Acute silencing (3 h) did not affect presynaptic markers or postsynaptic structures. To induce rapid, activity-dependent plasticity in striatal neurons, a chemical NMDA receptor-dependent “long-term potentiation (LTP)” paradigm was employed. Within 30 min, this increased spine and GluA1 cluster densities, and the percentage of spines containing GluA1 clusters, without altering the presynaptic signal. The results demonstrate that the growth and pruning of dendritic protrusions is an active process, requiring glutamate receptor activity in striatal projection neurons. Furthermore, NMDA receptor activation is sufficient to drive glutamatergic structural plasticity in SPNs, in the absence of dopamine or other neuromodulators.
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Affiliation(s)
- Naila Kuhlmann
- Centre for Applied Neurogenetics (CAN), University of British Columbia, Vancouver, BC, Canada.,Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | | | - Lucía Quesada-Ramírez
- Centre for Applied Neurogenetics (CAN), University of British Columbia, Vancouver, BC, Canada
| | - Matthew J Farrer
- Centre for Applied Neurogenetics (CAN), University of British Columbia, Vancouver, BC, Canada.,McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Austen J Milnerwood
- Centre for Applied Neurogenetics (CAN), University of British Columbia, Vancouver, BC, Canada.,Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
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20
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Stojakovic A, Chang SY, Nesbitt J, Pichurin NP, Ostroot MA, Aikawa T, Kanekiyo T, Trushina E. Partial Inhibition of Mitochondrial Complex I Reduces Tau Pathology and Improves Energy Homeostasis and Synaptic Function in 3xTg-AD Mice. J Alzheimers Dis 2021; 79:335-353. [PMID: 33285637 PMCID: PMC7902954 DOI: 10.3233/jad-201015] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background: Accumulation of hyperphosphorylated tau (pTau) protein is associated with synaptic dysfunction in Alzheimer’s disease (AD). We previously demonstrated that neuroprotection in familial mouse models of AD could be achieved by targeting mitochondria complex I (MCI) and activating the adaptive stress response. Efficacy of this strategy on pTau-related pathology remained unknown. Objective: To investigate the effect of specific MCI inhibitor tricyclic pyrone compound CP2 on levels of human pTau, memory function, long term potentiation (LTP), and energy homeostasis in 18-month-old 3xTg-AD mice and explore the potential mechanisms. Methods: CP2 was administered to male and female 3xTg-AD mice from 3.5–18 months of age. Cognitive function was assessed using the Morris water maze. Glucose metabolism was measured in periphery using a glucose tolerance test and in the brain using fluorodeoxyglucose F18 positron-emission tomography (FDG-PET). LTP was evaluated using electrophysiology in the hippocampus. The expression of key proteins associated with neuroprotective mechanisms were assessed by western blotting. Results: Chronic CP2 treatment restored synaptic activity in female 3xTg-AD mice; cognitive function, levels of synaptic proteins, glucose metabolism, and energy homeostasis were improved in male and female 3xTg-AD mice. Significant reduction of human pTau in the brain was associated with increased activity of protein phosphatase of type 2A (PP2A), and reduced activity of cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3β (GSK3β). Conclusion: CP2 treatment protected against synaptic dysfunction and memory impairment in symptomatic 3xTg-AD mice, and reduced levels of human pTau, indicating that targeting mitochondria with small molecule specific MCI inhibitors represents a promising strategy for treating AD.
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Affiliation(s)
| | - Su-Youne Chang
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, USA.,Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Jarred Nesbitt
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | | | - Mark A Ostroot
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Tomonori Aikawa
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | - Eugenia Trushina
- Department of Neurology, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
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21
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McCauley JP, Petroccione MA, D'Brant LY, Todd GC, Affinnih N, Wisnoski JJ, Zahid S, Shree S, Sousa AA, De Guzman RM, Migliore R, Brazhe A, Leapman RD, Khmaladze A, Semyanov A, Zuloaga DG, Migliore M, Scimemi A. Circadian Modulation of Neurons and Astrocytes Controls Synaptic Plasticity in Hippocampal Area CA1. Cell Rep 2020; 33:108255. [PMID: 33053337 PMCID: PMC7700820 DOI: 10.1016/j.celrep.2020.108255] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 08/21/2020] [Accepted: 09/18/2020] [Indexed: 12/18/2022] Open
Abstract
Most animal species operate according to a 24-h period set by the suprachiasmatic nucleus (SCN) of the hypothalamus. The rhythmic activity of the SCN modulates hippocampal-dependent memory, but the molecular and cellular mechanisms that account for this effect remain largely unknown. Here, we identify cell-type-specific structural and functional changes that occur with circadian rhythmicity in neurons and astrocytes in hippocampal area CA1. Pyramidal neurons change the surface expression of NMDA receptors. Astrocytes change their proximity to synapses. Together, these phenomena alter glutamate clearance, receptor activation, and integration of temporally clustered excitatory synaptic inputs, ultimately shaping hippocampal-dependent learning in vivo. We identify corticosterone as a key contributor to changes in synaptic strength. These findings highlight important mechanisms through which neurons and astrocytes modify the molecular composition and structure of the synaptic environment, contribute to the local storage of information in the hippocampus, and alter the temporal dynamics of cognitive processing.
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Affiliation(s)
- John P McCauley
- Department of Biology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | | | - Lianna Y D'Brant
- Department of Biology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA; Department of Physics, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Gabrielle C Todd
- Department of Biology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Nurat Affinnih
- Department of Biology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Justin J Wisnoski
- Department of Biology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Shergil Zahid
- Department of Biology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Swasti Shree
- Department of Biology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA; Bethlehem Central High School, 700 Delaware Avenue, Delmar, NY 12054, USA
| | - Alioscka A Sousa
- Federal University of São Paulo, Department of Biochemistry, 100 Rua Tres de Maio, São Paulo 04044-020, Brazil; National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Rose M De Guzman
- Department of Psychology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Rosanna Migliore
- Institute of Biophysics, National Research Council, 153 Via Ugo La Malfa, Palermo 90146, Italy
| | - Alexey Brazhe
- Department of Biophysics, Lomonosov Moscow State University, Leninskie Gory 1/12, Moscow 119234, Russia; Department of Molecular Neurobiology, Institute of Bioorganic Chemistry, Ulitsa Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Richard D Leapman
- National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Alexander Khmaladze
- Department of Physics, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Alexey Semyanov
- Department of Molecular Neurobiology, Institute of Bioorganic Chemistry, Ulitsa Miklukho-Maklaya 16/10, Moscow 117997, Russia; Sechenov First Moscow State Medical University, Bolshaya Pirogovskaya Ulitsa 19с1, Moscow 119146, Russia
| | - Damian G Zuloaga
- Department of Psychology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Michele Migliore
- Institute of Biophysics, National Research Council, 153 Via Ugo La Malfa, Palermo 90146, Italy
| | - Annalisa Scimemi
- Department of Biology, SUNY Albany, 1400 Washington Avenue, Albany, NY 12222, USA.
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22
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Nguyen PT, Dorman LC, Pan S, Vainchtein ID, Han RT, Nakao-Inoue H, Taloma SE, Barron JJ, Molofsky AB, Kheirbek MA, Molofsky AV. Microglial Remodeling of the Extracellular Matrix Promotes Synapse Plasticity. Cell 2020; 182:388-403.e15. [PMID: 32615087 DOI: 10.1016/j.cell.2020.05.050] [Citation(s) in RCA: 304] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 04/20/2020] [Accepted: 05/27/2020] [Indexed: 12/21/2022]
Abstract
Synapse remodeling is essential to encode experiences into neuronal circuits. Here, we define a molecular interaction between neurons and microglia that drives experience-dependent synapse remodeling in the hippocampus. We find that the cytokine interleukin-33 (IL-33) is expressed by adult hippocampal neurons in an experience-dependent manner and defines a neuronal subset primed for synaptic plasticity. Loss of neuronal IL-33 or the microglial IL-33 receptor leads to impaired spine plasticity, reduced newborn neuron integration, and diminished precision of remote fear memories. Memory precision and neuronal IL-33 are decreased in aged mice, and IL-33 gain of function mitigates age-related decreases in spine plasticity. We find that neuronal IL-33 instructs microglial engulfment of the extracellular matrix (ECM) and that its loss leads to impaired ECM engulfment and a concomitant accumulation of ECM proteins in contact with synapses. These data define a cellular mechanism through which microglia regulate experience-dependent synapse remodeling and promote memory consolidation.
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Affiliation(s)
- Phi T Nguyen
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Leah C Dorman
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Simon Pan
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Ilia D Vainchtein
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Rafael T Han
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Hiromi Nakao-Inoue
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Sunrae E Taloma
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Jerika J Barron
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Ari B Molofsky
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Mazen A Kheirbek
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA
| | - Anna V Molofsky
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA.
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23
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Zaccard CR, Shapiro L, Martin-de-Saavedra MD, Pratt C, Myczek K, Song A, Forrest MP, Penzes P. Rapid 3D Enhanced Resolution Microscopy Reveals Diversity in Dendritic Spinule Dynamics, Regulation, and Function. Neuron 2020; 107:522-537.e6. [PMID: 32464088 DOI: 10.1016/j.neuron.2020.04.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 12/19/2019] [Accepted: 04/27/2020] [Indexed: 12/31/2022]
Abstract
Dendritic spinules are thin protrusions, formed by neuronal spines, not adequately resolved by diffraction-limited light microscopy, which has limited our understanding of their behavior. Here we performed rapid structured illumination microscopy and enhanced resolution confocal microscopy to study spatiotemporal spinule dynamics in cortical pyramidal neurons. Spinules recurred at the same locations on mushroom spine heads. Most were short-lived, dynamic, exploratory, and originated near simple PSDs, whereas a subset was long-lived, elongated, and associated with complex PSDs. These subtypes were differentially regulated by Ca2+ transients. Furthermore, the postsynaptic Rac1-GEF kalirin-7 regulated spinule formation, elongation, and recurrence. Long-lived spinules often contained PSD fragments, contacted distal presynaptic terminals, and formed secondary synapses. NMDAR activation increased spinule number, length, and contact with distal presynaptic elements. Spinule subsets, dynamics, and recurrence were validated in cortical neurons of acute brain slices. Thus, we identified unique properties, regulatory mechanisms, and functions of spinule subtypes, supporting roles in neuronal connectivity.
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Affiliation(s)
- Colleen R Zaccard
- Department of Physiology, Northwestern University, Chicago, IL 60611, USA
| | - Lauren Shapiro
- Department of Physiology, Northwestern University, Chicago, IL 60611, USA
| | | | - Christopher Pratt
- Department of Physiology, Northwestern University, Chicago, IL 60611, USA
| | - Kristoffer Myczek
- Department of Physiology, Northwestern University, Chicago, IL 60611, USA
| | - Amy Song
- Department of Physiology, Northwestern University, Chicago, IL 60611, USA
| | - Marc P Forrest
- Department of Physiology, Northwestern University, Chicago, IL 60611, USA
| | - Peter Penzes
- Department of Physiology, Northwestern University, Chicago, IL 60611, USA; Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, IL 60611, USA.
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24
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Rantamäki T, Kohtala S. Encoding, Consolidation, and Renormalization in Depression: Synaptic Homeostasis, Plasticity, and Sleep Integrate Rapid Antidepressant Effects. Pharmacol Rev 2020; 72:439-465. [DOI: 10.1124/pr.119.018697] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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25
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Ren T, Chen P, Gu L, Ogut MG, Demirci U. Soft Ring-Shaped Cellu-Robots with Simultaneous Locomotion in Batches. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1905713. [PMID: 31773837 DOI: 10.1002/adma.201905713] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/20/2019] [Indexed: 06/10/2023]
Abstract
Untethered mini-robots can move single cells or aggregates to build complex constructs in confined spaces and may enable various biomedical applications such as regenerative repair in medicine and biosensing in bioengineering. However, a significant challenge is the ability to control multiple microrobots simultaneously in the same space to operate toward a common goal in a distributed operation. A locomotion strategy that can simultaneously guide the formation and operation of multiple robots in response to a common acoustic stimulus is developed. The scaffold-free cellu-robots comprise only highly packed cells and eliminate the influence of supportive materials, making them less cumbersome during locomotion. The ring shape of the cellu-robot contributes to anisotropic cellular interactions which induce radial cellular orientation. Under a single stimulus, several cellu-robots form predetermined complex structures such as bracelet-like ring-chains which transform into a single new living entity through cell-cell interactions, migration or cellular extensions between cellu-robots.
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Affiliation(s)
- Tanchen Ren
- Bio-Acoustic MEMS in Medicine (BAMM) Laboratory, Canary Center at Stanford for Cancer Early Detection, Department of Radiology, Stanford School of Medicine, Palo Alto, CA, 94304, USA
| | - Pu Chen
- Department of Biomedical Engineering, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430050, China
| | - Longjun Gu
- Department of Biomedical Engineering, Wuhan University School of Basic Medical Sciences, Wuhan, 430071, China
| | - Mehmet Giray Ogut
- Bio-Acoustic MEMS in Medicine (BAMM) Laboratory, Canary Center at Stanford for Cancer Early Detection, Department of Radiology, Stanford School of Medicine, Palo Alto, CA, 94304, USA
| | - Utkan Demirci
- Bio-Acoustic MEMS in Medicine (BAMM) Laboratory, Canary Center at Stanford for Cancer Early Detection, Department of Radiology, Stanford School of Medicine, Palo Alto, CA, 94304, USA
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26
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Abstract
The structure of neuronal circuits that subserve cognitive functions in the brain is shaped and refined throughout development and into adulthood. Evidence from human and animal studies suggests that the cellular and synaptic substrates of these circuits are atypical in neuropsychiatric disorders, indicating that altered structural plasticity may be an important part of the disease biology. Advances in genetics have redefined our understanding of neuropsychiatric disorders and have revealed a spectrum of risk factors that impact pathways known to influence structural plasticity. In this Review, we discuss the importance of recent genetic findings on the different mechanisms of structural plasticity and propose that these converge on shared pathways that can be targeted with novel therapeutics.
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27
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Glasgow SD, McPhedrain R, Madranges JF, Kennedy TE, Ruthazer ES. Approaches and Limitations in the Investigation of Synaptic Transmission and Plasticity. Front Synaptic Neurosci 2019; 11:20. [PMID: 31396073 PMCID: PMC6667546 DOI: 10.3389/fnsyn.2019.00020] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/04/2019] [Indexed: 12/16/2022] Open
Abstract
The numbers and strengths of synapses in the brain change throughout development, and even into adulthood, as synaptic inputs are added, eliminated, and refined in response to ongoing neural activity. A number of experimental techniques can assess these changes, including single-cell electrophysiological recording which offers measurements of synaptic inputs with high temporal resolution. Coupled with electrical stimulation, photoactivatable opsins, and caged compounds, to facilitate fine spatiotemporal control over release of neurotransmitters, electrophysiological recordings allow for precise dissection of presynaptic and postsynaptic mechanisms of action. Here, we discuss the strengths and pitfalls of various techniques commonly used to analyze synapses, including miniature excitatory/inhibitory (E/I) postsynaptic currents, evoked release, and optogenetic stimulation. Together, these techniques can provide multiple lines of convergent evidence to generate meaningful insight into the emergence of circuit connectivity and maturation. A full understanding of potential caveats and alternative explanations for findings is essential to avoid data misinterpretation.
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Affiliation(s)
| | | | | | | | - Edward S. Ruthazer
- Department of Neurology & Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC, Canada
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28
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Quinn DP, Kolar A, Harris SA, Wigerius M, Fawcett JP, Krueger SR. The Stability of Glutamatergic Synapses Is Independent of Activity Level, but Predicted by Synapse Size. Front Cell Neurosci 2019; 13:291. [PMID: 31316356 PMCID: PMC6609312 DOI: 10.3389/fncel.2019.00291] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 06/14/2019] [Indexed: 01/23/2023] Open
Abstract
Neuronal activity is thought to drive the remodeling of circuits in the mammalian cerebral cortex. However, its precise function in the underlying formation and elimination of glutamatergic synapses has remained controversial. To clarify the role of activity in synapse turnover, we have assessed the effects of inhibition of glutamate release from a sparse subset of cultured hippocampal neurons on synapse turnover. Sustained chemogenetic attenuation of release through presynaptic expression of a designer receptor exclusively activated by designer drugs (DREADD) had no effect on the formation or elimination of glutamatergic synapses. Sparse expression of tetanus neurotoxin light chain (TeNT-LC), a synaptobrevin-cleaving protease that completely abolishes neurotransmitter release, likewise did not lead to changes in the rate of synapse elimination, although it reduced the rate of synapse formation. The stability of active and silenced synapses correlated with measures of synapse size. While not excluding a modulatory role in synapse elimination, our findings show that synaptic activity is neither required for the removal nor the maintenance of glutamatergic synapses between hippocampal neurons. Our results also demonstrate that the stability of glutamatergic synapses scales with their size irrespective of their activity.
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Affiliation(s)
- Dylan P Quinn
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada.,Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Annette Kolar
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Sydney A Harris
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Michael Wigerius
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - James P Fawcett
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Stefan R Krueger
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
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29
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Ji J, Moquin A, Bertorelle F, KY Chang P, Antoine R, Luo J, McKinney RA, Maysinger D. Organotypic and primary neural cultures as models to assess effects of different gold nanostructures on glia and neurons. Nanotoxicology 2019; 13:285-304. [DOI: 10.1080/17435390.2018.1543468] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Jeff Ji
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - Alexandre Moquin
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - Franck Bertorelle
- CNRS, Institut Lumière Matière, Université Lyon Université Claude Bernard Lyon 1, Lyon, France
| | - Philip KY Chang
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - Rodolphe Antoine
- CNRS, Institut Lumière Matière, Université Lyon Université Claude Bernard Lyon 1, Lyon, France
| | - Julia Luo
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - R. Anne McKinney
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - Dusica Maysinger
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
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30
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More JY, Bruna BA, Lobos PE, Galaz JL, Figueroa PL, Namias S, Sánchez GL, Barrientos GC, Valdés JL, Paula-Lima AC, Hidalgo C, Adasme T. Calcium Release Mediated by Redox-Sensitive RyR2 Channels Has a Central Role in Hippocampal Structural Plasticity and Spatial Memory. Antioxid Redox Signal 2018; 29:1125-1146. [PMID: 29357673 DOI: 10.1089/ars.2017.7277] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIMS Previous studies indicate that hippocampal synaptic plasticity and spatial memory processes entail calcium release from intracellular stores mediated by ryanodine receptor (RyR) channels. In particular, RyR-mediated Ca2+ release is central for the dendritic spine remodeling induced by brain-derived neurotrophic factor (BDNF), a neurotrophin that stimulates complex signaling pathways leading to memory-associated protein synthesis and structural plasticity. To examine if upregulation of ryanodine receptor type-2 (RyR2) channels and the spine remodeling induced by BDNF entail reactive oxygen species (ROS) generation, and to test if RyR2 downregulation affects BDNF-induced spine remodeling and spatial memory. RESULTS Downregulation of RyR2 expression (short hairpin RNA [shRNA]) in primary hippocampal neurons, or inhibition of nitric oxide synthase (NOS) or NADPH oxidase, prevented agonist-mediated RyR-mediated Ca2+ release, whereas BDNF promoted cytoplasmic ROS generation. RyR2 downregulation or inhibitors of N-methyl-d-aspartate (NMDA) receptors, or NOS or of NADPH oxidase type-2 (NOX2) prevented RyR2 upregulation and the spine remodeling induced by BDNF, as did incubation with the antioxidant agent N-acetyl l-cysteine. In addition, intrahippocampal injection of RyR2-directed antisense oligodeoxynucleotides, which caused significant RyR2 downregulation, caused conspicuous defects in a memorized spatial memory task. INNOVATION The present novel results emphasize the key role of redox-sensitive Ca2+ release mediated by RyR2 channels for hippocampal structural plasticity and spatial memory. CONCLUSION Based on these combined results, we propose (i) that BDNF-induced RyR2-mediated Ca2+ release and ROS generation via NOS/NOX2 are strictly required for the dendritic spine remodeling and the RyR2 upregulation induced by BDNF, and (ii) that RyR2 channel expression is crucial for spatial memory processes. Antioxid. Redox Signal. 29, 1125-1146.
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Affiliation(s)
- Jamileth Y More
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Barbara A Bruna
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Pedro E Lobos
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - José L Galaz
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Paula L Figueroa
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Silvia Namias
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Gina L Sánchez
- 2 Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Genaro C Barrientos
- 2 Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - José L Valdés
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile .,3 Department of Neuroscience, Faculty of Medicine, Universidad de Chile , Santiago, Chile
| | - Andrea C Paula-Lima
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile .,4 Institute for Research in Dental Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile .,2 Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile .,3 Department of Neuroscience, Faculty of Medicine, Universidad de Chile , Santiago, Chile .,5 Center for Exercise , Metabolism and Cancer Studies, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Tatiana Adasme
- 1 Biomedical Neuroscience Institute , Faculty of Medicine, Universidad de Chile, Santiago, Chile .,6 Centro Integrativo de Biología y Química Aplicada, Universidad Bernardo O'Higgins , Santiago, Chile
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31
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Hacohen-Kleiman G, Sragovich S, Karmon G, Gao AYL, Grigg I, Pasmanik-Chor M, Le A, Korenková V, McKinney RA, Gozes I. Activity-dependent neuroprotective protein deficiency models synaptic and developmental phenotypes of autism-like syndrome. J Clin Invest 2018; 128:4956-4969. [PMID: 30106381 DOI: 10.1172/jci98199] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 07/31/2018] [Indexed: 12/11/2022] Open
Abstract
Previous findings showed that in mice, complete knockout of activity-dependent neuroprotective protein (ADNP) abolishes brain formation, while haploinsufficiency (Adnp+/-) causes cognitive impairments. We hypothesized that mutations in ADNP lead to a developmental/autistic syndrome in children. Indeed, recent phenotypic characterization of children harboring ADNP mutations (ADNP syndrome children) revealed global developmental delays and intellectual disabilities, including speech and motor dysfunctions. Mechanistically, ADNP includes a SIP motif embedded in the ADNP-derived snippet drug candidate NAP (NAPVSIPQ, also known as CP201), which binds to microtubule end-binding protein 3, essential for dendritic spine formation. Here, we established a unique neuronal membrane-tagged, GFP-expressing Adnp+/- mouse line allowing in vivo synaptic pathology quantification. We discovered that Adnp deficiency reduced dendritic spine density and altered synaptic gene expression, both of which were partly ameliorated by NAP treatment. Adnp+/-mice further exhibited global developmental delays, vocalization impediments, gait and motor dysfunctions, and social and object memory impairments, all of which were partially reversed by daily NAP administration (systemic/nasal). In conclusion, we have connected ADNP-related synaptic pathology to developmental and behavioral outcomes, establishing NAP in vivo target engagement and identifying potential biomarkers. Together, these studies pave a path toward the clinical development of NAP (CP201) for the treatment of ADNP syndrome.
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Affiliation(s)
- Gal Hacohen-Kleiman
- The Lily and Avraham Gildor Chair for the Investigation of Growth Factors; The Elton Laboratory for Neuroendocrinology; Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Sagol School of Neuroscience and Adams Super Center for Brain Studies, Tel Aviv University, Tel Aviv, Israel
| | - Shlomo Sragovich
- The Lily and Avraham Gildor Chair for the Investigation of Growth Factors; The Elton Laboratory for Neuroendocrinology; Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Sagol School of Neuroscience and Adams Super Center for Brain Studies, Tel Aviv University, Tel Aviv, Israel
| | - Gidon Karmon
- The Lily and Avraham Gildor Chair for the Investigation of Growth Factors; The Elton Laboratory for Neuroendocrinology; Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Sagol School of Neuroscience and Adams Super Center for Brain Studies, Tel Aviv University, Tel Aviv, Israel
| | - Andy Y L Gao
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Iris Grigg
- The Lily and Avraham Gildor Chair for the Investigation of Growth Factors; The Elton Laboratory for Neuroendocrinology; Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Sagol School of Neuroscience and Adams Super Center for Brain Studies, Tel Aviv University, Tel Aviv, Israel
| | - Metsada Pasmanik-Chor
- Bioinformatics Unit, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Albert Le
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | | | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Illana Gozes
- The Lily and Avraham Gildor Chair for the Investigation of Growth Factors; The Elton Laboratory for Neuroendocrinology; Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Sagol School of Neuroscience and Adams Super Center for Brain Studies, Tel Aviv University, Tel Aviv, Israel
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32
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Gruber L, Rybak J, Hansson BS, Cantera R. Synaptic Spinules in the Olfactory Circuit of Drosophila melanogaster. Front Cell Neurosci 2018; 12:86. [PMID: 29636666 PMCID: PMC5880883 DOI: 10.3389/fncel.2018.00086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/12/2018] [Indexed: 11/14/2022] Open
Abstract
Here we report on ultrastructural features of brain synapses in the fly Drosophila melanogaster and outline a perspective for the study of their functional significance. Images taken with the aid of focused ion beam-scanning electron microscopy (EM) at 20 nm intervals across olfactory glomerulus DA2 revealed that some synaptic boutons are penetrated by protrusions emanating from other neurons. Similar structures in the brain of mammals are known as synaptic spinules. A survey with transmission EM (TEM) disclosed that these structures are frequent throughout the antennal lobe. Detailed neuronal tracings revealed that spinules are formed by all three major types of neurons innervating glomerulus DA2 but the olfactory sensory neurons (OSNs) receive significantly more spinules than other olfactory neurons. Double-membrane vesicles (DMVs) that appear to represent material that has pinched-off from spinules are also most abundant in presynaptic boutons of OSNs. Inside the host neuron, a close association was observed between spinules, the endoplasmic reticulum (ER) and mitochondria. We propose that by releasing material into the host neuron, through a process triggered by synaptic activity and analogous to axonal pruning, synaptic spinules could function as a mechanism for synapse tagging, synaptic remodeling and neural plasticity. Future directions of experimental work to investigate this theory are proposed.
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Affiliation(s)
- Lydia Gruber
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology (MPG)Jena, Germany
| | - Jürgen Rybak
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology (MPG)Jena, Germany
| | - Bill S Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology (MPG)Jena, Germany
| | - Rafael Cantera
- Departamento de Biología del Neurodesarrollo, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE)Montevideo, Uruguay.,Zoology Department, Stockholm UniversityStockholm, Sweden
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33
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Weinhard L, di Bartolomei G, Bolasco G, Machado P, Schieber NL, Neniskyte U, Exiga M, Vadisiute A, Raggioli A, Schertel A, Schwab Y, Gross CT. Microglia remodel synapses by presynaptic trogocytosis and spine head filopodia induction. Nat Commun 2018; 9:1228. [PMID: 29581545 PMCID: PMC5964317 DOI: 10.1038/s41467-018-03566-5] [Citation(s) in RCA: 507] [Impact Index Per Article: 84.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 02/22/2018] [Indexed: 01/09/2023] Open
Abstract
Microglia are highly motile glial cells that are proposed to mediate synaptic pruning during neuronal circuit formation. Disruption of signaling between microglia and neurons leads to an excess of immature synaptic connections, thought to be the result of impaired phagocytosis of synapses by microglia. However, until now the direct phagocytosis of synapses by microglia has not been reported and fundamental questions remain about the precise synaptic structures and phagocytic mechanisms involved. Here we used light sheet fluorescence microscopy to follow microglia–synapse interactions in developing organotypic hippocampal cultures, complemented by a 3D ultrastructural characterization using correlative light and electron microscopy (CLEM). Our findings define a set of dynamic microglia–synapse interactions, including the selective partial phagocytosis, or trogocytosis (trogo-: nibble), of presynaptic structures and the induction of postsynaptic spine head filopodia by microglia. These findings allow us to propose a mechanism for the facilitatory role of microglia in synaptic circuit remodeling and maturation. Direct visualization of microglia-mediated synapse pruning has been lacking. This study shows direct evidence of microglia-synapse interaction where microglia do not necessarily ‘eat’ post-synaptic structure but ‘nibble’ on pre-synaptic terminals, much akin to trogocytosis by lymphocytes.
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Affiliation(s)
- Laetitia Weinhard
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015, Monterotondo, Italy
| | - Giulia di Bartolomei
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015, Monterotondo, Italy
| | - Giulia Bolasco
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015, Monterotondo, Italy
| | - Pedro Machado
- Electron Microscopy Core Facility, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Nicole L Schieber
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Urte Neniskyte
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015, Monterotondo, Italy.,Department of Neurobiology and Biophysics, Life Science Center, Vilnius University, Sauletekio al. 7, Vilnius, 10257, Lithuania
| | - Melanie Exiga
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015, Monterotondo, Italy
| | - Auguste Vadisiute
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015, Monterotondo, Italy.,Department of Neurobiology and Biophysics, Life Science Center, Vilnius University, Sauletekio al. 7, Vilnius, 10257, Lithuania
| | - Angelo Raggioli
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015, Monterotondo, Italy
| | - Andreas Schertel
- Carl Zeiss Microscopy GmbH, ZEISS Group, Carl-Zeiss-Strasse 22, 73447, Oberkochen, Germany
| | - Yannick Schwab
- Electron Microscopy Core Facility, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Cornelius T Gross
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015, Monterotondo, Italy.
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34
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Maysinger D, Ji J, Moquin A, Hossain S, Hancock MA, Zhang I, Chang PK, Rigby M, Anthonisen M, Grütter P, Breitner J, McKinney RA, Reimann S, Haag R, Multhaup G. Dendritic Polyglycerol Sulfates in the Prevention of Synaptic Loss and Mechanism of Action on Glia. ACS Chem Neurosci 2018; 9:260-271. [PMID: 29078046 DOI: 10.1021/acschemneuro.7b00301] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Dendritic polyglycerols (dPG), particularly dendritic polyglycerol sulfates (dPGS), have been intensively studied due to their intrinsic anti-inflammatory activity. As related to brain pathologies involving neuroinflammation, the current study examined if dPG and dPGS can (i) regulate neuroglial activation, and (ii) normalize the morphology and function of excitatory postsynaptic dendritic spines adversely affected by the neurotoxic 42 amino acid amyloid-β (Aβ42) peptide of Alzheimer disease (AD). The exact role of neuroglia, such as microglia and astrocytes, remains controversial especially their positive and negative impact on inflammatory processes in AD. To test dPGS effectiveness in AD models we used primary neuroglia and organotypic hippocampal slice cultures exposed to Aβ42 peptide. Overall, our data indicate that dPGS is taken up by both microglia and astrocytes in a concentration- and time-dependent manner. The mechanism of action of dPGS involves binding to Aβ42, i.e., a direct interaction between dPGS and Aβ42 species interfered with Aβ fibril formation and reduced the production of the neuroinflammagen lipocalin-2 (LCN2) mainly in astrocytes. Moreover, dPGS normalized the impairment of neuroglia and prevented the loss of dendritic spines at excitatory synapses in the hippocampus. In summary, dPGS has desirable therapeutic properties that may help reduce amyloid-induced neuroinflammation and neurotoxicity in AD.
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Affiliation(s)
- Dusica Maysinger
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
| | - Jeff Ji
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
| | - Alexandre Moquin
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
| | - Shireen Hossain
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
| | - Mark A. Hancock
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
| | - Issan Zhang
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
| | - Philip K.Y. Chang
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
| | - Matthew Rigby
- Department
of Physics, McGill University, Montreal, Canada H3A 2T8
| | | | - Peter Grütter
- Department
of Physics, McGill University, Montreal, Canada H3A 2T8
| | - John Breitner
- Douglas
Hospital Research Centre, McGill University, Montreal, Canada H4H 1R3
| | - R. Anne McKinney
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
| | - Sabine Reimann
- Institut
für Chemie und Biochemie, Freie Universität Berlin, 14195 Berlin, Germany
| | - Rainer Haag
- Institut
für Chemie und Biochemie, Freie Universität Berlin, 14195 Berlin, Germany
| | - Gerhard Multhaup
- Department
of Pharmacology and Therapeutics, McGill University, Montreal, Canada H3G 1Y6
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Assembly of Excitatory Synapses in the Absence of Glutamatergic Neurotransmission. Neuron 2017; 94:312-321.e3. [PMID: 28426966 DOI: 10.1016/j.neuron.2017.03.047] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 02/26/2017] [Accepted: 03/30/2017] [Indexed: 11/22/2022]
Abstract
Synaptic excitation mediates a broad spectrum of structural changes in neural circuits across the brain. Here, we examine the morphologies, wiring, and architectures of single synapses of projection neurons in the murine hippocampus that developed in virtually complete absence of vesicular glutamate release. While these neurons had smaller dendritic trees and/or formed fewer contacts in specific hippocampal subfields, their stereotyped connectivity was largely preserved. Furthermore, loss of release did not disrupt the morphogenesis of presynaptic terminals and dendritic spines, suggesting that glutamatergic neurotransmission is unnecessary for synapse assembly and maintenance. These results underscore the instructive role of intrinsic mechanisms in synapse formation.
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Formation and Maintenance of Functional Spines in the Absence of Presynaptic Glutamate Release. Neuron 2017; 94:304-311.e4. [PMID: 28426965 PMCID: PMC5418202 DOI: 10.1016/j.neuron.2017.03.029] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 02/17/2017] [Accepted: 03/22/2017] [Indexed: 11/22/2022]
Abstract
Dendritic spines are the major transmitter reception compartments of glutamatergic synapses in most principal neurons of the mammalian brain and play a key role in the function of nerve cell circuits. The formation of functional spine synapses is thought to be critically dependent on presynaptic glutamatergic signaling. By analyzing CA1 pyramidal neurons in mutant hippocampal slice cultures that are essentially devoid of presynaptic transmitter release, we demonstrate that the formation and maintenance of dendrites and functional spines are independent of synaptic glutamate release.
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Miyazaki T, Yamasaki M, Hashimoto K, Kohda K, Yuzaki M, Shimamoto K, Tanaka K, Kano M, Watanabe M. Glutamate transporter GLAST controls synaptic wrapping by Bergmann glia and ensures proper wiring of Purkinje cells. Proc Natl Acad Sci U S A 2017; 114:7438-7443. [PMID: 28655840 PMCID: PMC5514701 DOI: 10.1073/pnas.1617330114] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Astrocytes regulate synaptic transmission through controlling neurotransmitter concentrations around synapses. Little is known, however, about their roles in neural circuit development. Here we report that Bergmann glia (BG), specialized cerebellar astrocytes that thoroughly enwrap Purkinje cells (PCs), are essential for synaptic organization in PCs through the action of the l-glutamate/l-aspartate transporter (GLAST). In GLAST-knockout mice, dendritic innervation by the main ascending climbing fiber (CF) branch was significantly weakened, whereas the transverse branch, which is thin and nonsynaptogenic in control mice, was transformed into thick and synaptogenic branches. Both types of CF branches frequently produced aberrant wiring to proximal and distal dendrites, causing multiple CF-PC innervation. Our electrophysiological analysis revealed that slow and small CF-evoked excitatory postsynaptic currents (EPSCs) were recorded from almost all PCs in GLAST-knockout mice. These atypical CF-EPSCs were far more numerous and had significantly faster 10-90% rise time than those elicited by glutamate spillover under pharmacological blockade of glial glutamate transporters. Innervation by parallel fibers (PFs) was also affected. PF synapses were robustly increased in the entire dendritic trees, leading to impaired segregation of CF and PF territories. Furthermore, lamellate BG processes were retracted from PC dendrites and synapses, leading to the exposure of these neuronal elements to the extracellular milieus. These synaptic and glial phenotypes were reproduced in wild-type mice after functional blockade of glial glutamate transporters. These findings highlight that glutamate transporter function by GLAST on BG plays important roles in development and maintenance of proper synaptic wiring and wrapping in PCs.
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Affiliation(s)
- Taisuke Miyazaki
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Miwako Yamasaki
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Kouichi Hashimoto
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Hongo, Tokyo 113-0033, Japan
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8551, Japan
| | - Kazuhisa Kohda
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Department of Physiology, St. Marianna University School of Medicine, Kanagawa 216-8511, Japan
| | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Keiko Shimamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, 619-0284, Japan
| | - Kohichi Tanaka
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Hongo, Tokyo 113-0033, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan;
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Gipson CD, Olive MF. Structural and functional plasticity of dendritic spines - root or result of behavior? GENES BRAIN AND BEHAVIOR 2016; 16:101-117. [PMID: 27561549 DOI: 10.1111/gbb.12324] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/19/2016] [Accepted: 08/24/2016] [Indexed: 02/06/2023]
Abstract
Dendritic spines are multifunctional integrative units of the nervous system and are highly diverse and dynamic in nature. Both internal and external stimuli influence dendritic spine density and morphology on the order of minutes. It is clear that the structural plasticity of dendritic spines is related to changes in synaptic efficacy, learning and memory and other cognitive processes. However, it is currently unclear whether structural changes in dendritic spines are primary instigators of changes in specific behaviors, a consequence of behavioral changes, or both. In this review, we first examine the basic structure and function of dendritic spines in the brain, as well as laboratory methods to characterize and quantify morphological changes in dendritic spines. We then discuss the existing literature on the temporal and functional relationship between changes in dendritic spines in specific brain regions and changes in specific behaviors mediated by those regions. Although technological advancements have allowed us to better understand the functional relevance of structural changes in dendritic spines that are influenced by environmental stimuli, the role of spine dynamics as an underlying driver or consequence of behavior still remains elusive. We conclude that while it is likely that structural changes in dendritic spines are both instigators and results of behavioral changes, improved research tools and methods are needed to experimentally and directly manipulate spine dynamics in order to more empirically delineate the relationship between spine structure and behavior.
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Affiliation(s)
- C D Gipson
- Department of Psychology, Arizona State University, Tempe, AZ, USA
| | - M F Olive
- Department of Psychology, Arizona State University, Tempe, AZ, USA
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Spiess R, George R, Cook M, Diehl PU. Structural Plasticity Denoises Responses and Improves Learning Speed. Front Comput Neurosci 2016; 10:93. [PMID: 27660610 PMCID: PMC5014863 DOI: 10.3389/fncom.2016.00093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 08/23/2016] [Indexed: 11/13/2022] Open
Abstract
Despite an abundance of computational models for learning of synaptic weights, there has been relatively little research on structural plasticity, i.e., the creation and elimination of synapses. Especially, it is not clear how structural plasticity works in concert with spike-timing-dependent plasticity (STDP) and what advantages their combination offers. Here we present a fairly large-scale functional model that uses leaky integrate-and-fire neurons, STDP, homeostasis, recurrent connections, and structural plasticity to learn the input encoding, the relation between inputs, and to infer missing inputs. Using this model, we compare the error and the amount of noise in the network's responses with and without structural plasticity and the influence of structural plasticity on the learning speed of the network. Using structural plasticity during learning shows good results for learning the representation of input values, i.e., structural plasticity strongly reduces the noise of the response by preventing spikes with a high error. For inferring missing inputs we see similar results, with responses having less noise if the network was trained using structural plasticity. Additionally, using structural plasticity with pruning significantly decreased the time to learn weights suitable for inference. Presumably, this is due to the clearer signal containing less spikes that misrepresent the desired value. Therefore, this work shows that structural plasticity is not only able to improve upon the performance using STDP without structural plasticity but also speeds up learning. Additionally, it addresses the practical problem of limited resources for connectivity that is not only apparent in the mammalian neocortex but also in computer hardware or neuromorphic (brain-inspired) hardware by efficiently pruning synapses without losing performance.
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Affiliation(s)
- Robin Spiess
- Department of Computer Science, Swiss Federal Institute of Technology (ETH Zurich) Zurich, Switzerland
| | - Richard George
- Institute of Neuroinformatics, ETH Zurich and University Zurich Zurich, Switzerland
| | - Matthew Cook
- Institute of Neuroinformatics, ETH Zurich and University Zurich Zurich, Switzerland
| | - Peter U Diehl
- Institute of Neuroinformatics, ETH Zurich and University Zurich Zurich, Switzerland
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Principal cell activity induces spine relocation of adult-born interneurons in the olfactory bulb. Nat Commun 2016; 7:12659. [PMID: 27578235 PMCID: PMC5013674 DOI: 10.1038/ncomms12659] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 07/21/2016] [Indexed: 01/05/2023] Open
Abstract
Adult-born neurons adjust olfactory bulb (OB) network functioning in response to changing environmental conditions by the formation, retraction and/or stabilization of new synaptic contacts. While some changes in the odour environment are rapid, the synaptogenesis of adult-born neurons occurs over a longer time scale. It remains unknown how the bulbar network functions when rapid and persistent changes in environmental conditions occur but when new synapses have not been formed. Here we reveal a new form of structural remodelling where mature spines of adult-born but not early-born neurons relocate in an activity-dependent manner. Principal cell activity induces directional growth of spine head filopodia (SHF) followed by spine relocation. Principal cell-derived glutamate and BDNF regulate SHF motility and directional spine relocation, respectively; and spines with SHF are selectively preserved following sensory deprivation. Our three-dimensional model suggests that spine relocation allows fast reorganization of OB network with functional consequences for odour information processing. The mechanism by which adult-born neurons quickly adjust olfactory bulb network functioning is not understood. Here the authors describe a novel form of structural plasticity in which mature spines relocate toward active mitral cell dendrite along spine head filopodia via AMPA and BDNF mediated signalling.
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Parajuli LK, Tanaka S, Okabe S. Insights into age-old questions of new dendritic spines: From form to function. Brain Res Bull 2016; 129:3-11. [PMID: 27491624 DOI: 10.1016/j.brainresbull.2016.07.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/18/2016] [Accepted: 07/31/2016] [Indexed: 11/30/2022]
Abstract
Principal neurons in multiple brain regions receive a vast majority of excitatory synaptic contacts on the tiny dendritic appendages called dendritic spines. These structures are believed to be the locus of memory storage in the brain. Indeed, neurological diseases leading to impairment in memory and cognitive capabilities are often associated with structural alteration of dendritic spines. While several landmark studies in the past have provided a great deal of information on the structure, function and molecular composition of prototypical mature dendritic spines, we still have a limited knowledge of nascent spines. In recent years there has been a surge of interest to understand the nascent spines and the increasing technical advances in the genetic, molecular and imaging methods have opened avenues for systematic and thorough investigation. In this review, by discussing studies from several labs including ours, we provide a systematic summary of the development, structure, molecular expression and function of nascent spines and highlight some of the potentially important and interesting research questions that remain to be answered.
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Affiliation(s)
- Laxmi Kumar Parajuli
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shinji Tanaka
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
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Verbich D, Becker D, Vlachos A, Mundel P, Deller T, McKinney RA. Rewiring neuronal microcircuits of the brain via spine head protrusions--a role for synaptopodin and intracellular calcium stores. Acta Neuropathol Commun 2016; 4:38. [PMID: 27102112 PMCID: PMC4840984 DOI: 10.1186/s40478-016-0311-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/09/2016] [Indexed: 11/26/2022] Open
Abstract
Neurological diseases associated with neuronal death are also accompanied by axonal denervation of connected brain regions. In these areas, denervation leads to a decrease in afferent drive, which may in turn trigger active central nervous system (CNS) circuitry rearrangement. This rewiring process is important therapeutically, since it can partially recover functions and can be further enhanced using modern rehabilitation strategies. Nevertheless, the cellular mechanisms of brain rewiring are not fully understood. We recently reported a mechanism by which neurons remodel their local connectivity under conditions of network-perturbance: hippocampal pyramidal cells can extend spine head protrusions (SHPs), which reach out toward neighboring terminals and form new synapses. Since this form of activity-dependent rewiring is observed only on some spines, we investigated the required conditions. We speculated, that the actin-associated protein synaptopodin, which is involved in several synaptic plasticity mechanisms, could play a role in the formation and/or stabilization of SHPs. Using hippocampal slice cultures, we found that ~70 % of spines with protrusions in CA1 pyramidal neurons contained synaptopodin. Analysis of synaptopodin-deficient neurons revealed that synaptopodin is required for the stability but not the formation of SHPs. The effects of synaptopodin could be linked to its role in Ca2+ homeostasis, since spines with protrusions often contained ryanodine receptors and synaptopodin. Furthermore, disrupting Ca2+ signaling shortened protrusion lifetime. By transgenically reintroducing synaptopodin on a synaptopodin-deficient background, SHP stability could be rescued. Overall, we show that synaptopodin increases the stability of SHPs, and could potentially modulate the rewiring of microcircuitries by making synaptic reorganization more efficient.
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43
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Conant K, Allen M, Lim ST. Activity dependent CAM cleavage and neurotransmission. Front Cell Neurosci 2015; 9:305. [PMID: 26321910 PMCID: PMC4531370 DOI: 10.3389/fncel.2015.00305] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/27/2015] [Indexed: 12/13/2022] Open
Abstract
Spatially localized proteolysis represents an elegant means by which neuronal activity dependent changes in synaptic structure, and thus experience dependent learning and memory, can be achieved. In vitro and in vivo studies suggest that matrix metalloproteinase and adamalysin activity is concentrated at the cell surface, and emerging evidence suggests that increased peri-synaptic expression, release and/or activation of these proteinases occurs with enhanced excitatory neurotransmission. Synaptically expressed cell adhesion molecules (CAMs) could therefore represent important targets for neuronal activity-dependent proteolysis. Several CAM subtypes are expressed at the synapse, and their cleavage can influence the efficacy of synaptic transmission through a variety of non-mutually exclusive mechanisms. In the following review, we discuss mechanisms that regulate neuronal activity-dependent synaptic CAM shedding, including those that may be calcium dependent. We also highlight CAM targets of activity-dependent proteolysis including neuroligin and intercellular adhesion molecule-5 (ICAM-5). We include discussion focused on potential consequences of synaptic CAM shedding, with an emphasis on interactions between soluble CAM cleavage products and specific pre- and post-synaptic receptors.
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Affiliation(s)
- Katherine Conant
- Department of Neuroscience and Interdisciplinary Program in Neuroscience, Georgetown University Medical Center Washington, DC, USA
| | - Megan Allen
- Department of Neuroscience and Interdisciplinary Program in Neuroscience, Georgetown University Medical Center Washington, DC, USA
| | - Seung T Lim
- Department of Neuroscience and Interdisciplinary Program in Neuroscience, Georgetown University Medical Center Washington, DC, USA
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44
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Reinhard SM, Razak K, Ethell IM. A delicate balance: role of MMP-9 in brain development and pathophysiology of neurodevelopmental disorders. Front Cell Neurosci 2015; 9:280. [PMID: 26283917 PMCID: PMC4518323 DOI: 10.3389/fncel.2015.00280] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/09/2015] [Indexed: 12/27/2022] Open
Abstract
The extracellular matrix (ECM) is a critical regulator of neural network development and plasticity. As neuronal circuits develop, the ECM stabilizes synaptic contacts, while its cleavage has both permissive and active roles in the regulation of plasticity. Matrix metalloproteinase 9 (MMP-9) is a member of a large family of zinc-dependent endopeptidases that can cleave ECM and several cell surface receptors allowing for synaptic and circuit level reorganization. It is becoming increasingly clear that the regulated activity of MMP-9 is critical for central nervous system (CNS) development. In particular, MMP-9 has a role in the development of sensory circuits during early postnatal periods, called ‘critical periods.’ MMP-9 can regulate sensory-mediated, local circuit reorganization through its ability to control synaptogenesis, axonal pathfinding and myelination. Although activity-dependent activation of MMP-9 at specific synapses plays an important role in multiple plasticity mechanisms throughout the CNS, misregulated activation of the enzyme is implicated in a number of neurodegenerative disorders, including traumatic brain injury, multiple sclerosis, and Alzheimer’s disease. Growing evidence also suggests a role for MMP-9 in the pathophysiology of neurodevelopmental disorders including Fragile X Syndrome. This review outlines the various actions of MMP-9 during postnatal brain development, critical for future studies exploring novel therapeutic strategies for neurodevelopmental disorders.
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Affiliation(s)
- Sarah M Reinhard
- Psychology Department, University of California, Riverside Riverside, CA, USA
| | - Khaleel Razak
- Psychology Department, University of California, Riverside Riverside, CA, USA
| | - Iryna M Ethell
- Biomedical Sciences Division, School of Medicine, University of California, Riverside Riverside, CA, USA
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45
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Mandali A, Rengaswamy M, Chakravarthy VS, Moustafa AA. A spiking Basal Ganglia model of synchrony, exploration and decision making. Front Neurosci 2015; 9:191. [PMID: 26074761 PMCID: PMC4444758 DOI: 10.3389/fnins.2015.00191] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 05/12/2015] [Indexed: 12/31/2022] Open
Abstract
To make an optimal decision we need to weigh all the available options, compare them with the current goal, and choose the most rewarding one. Depending on the situation an optimal decision could be to either “explore” or “exploit” or “not to take any action” for which the Basal Ganglia (BG) is considered to be a key neural substrate. In an attempt to expand this classical picture of BG function, we had earlier hypothesized that the Indirect Pathway (IP) of the BG could be the subcortical substrate for exploration. In this study we build a spiking network model to relate exploration to synchrony levels in the BG (which are a neural marker for tremor in Parkinson's disease). Key BG nuclei such as the Sub Thalamic Nucleus (STN), Globus Pallidus externus (GPe) and Globus Pallidus internus (GPi) were modeled as Izhikevich spiking neurons whereas the Striatal output was modeled as Poisson spikes. The model is cast in reinforcement learning framework with the dopamine signal representing reward prediction error. We apply the model to two decision making tasks: a binary action selection task (similar to one used by Humphries et al., 2006) and an n-armed bandit task (Bourdaud et al., 2008). The model shows that exploration levels could be controlled by STN's lateral connection strength which also influenced the synchrony levels in the STN-GPe circuit. An increase in STN's lateral strength led to a decrease in exploration which can be thought as the possible explanation for reduced exploratory levels in Parkinson's patients. Our simulations also show that on complete removal of IP, the model exhibits only Go and No-Go behaviors, thereby demonstrating the crucial role of IP in exploration. Our model provides a unified account for synchronization, action section, and explorative behavior.
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Affiliation(s)
- Alekhya Mandali
- Computational Neuroscience Lab, Department of Biotechnology, Bhupat and Mehta School of BioSciences, Indian Institute of Technology Madras Chennai, India
| | - Maithreye Rengaswamy
- Computational Neuroscience Lab, Department of Biotechnology, Bhupat and Mehta School of BioSciences, Indian Institute of Technology Madras Chennai, India
| | - V Srinivasa Chakravarthy
- Computational Neuroscience Lab, Department of Biotechnology, Bhupat and Mehta School of BioSciences, Indian Institute of Technology Madras Chennai, India
| | - Ahmed A Moustafa
- Marcs Institute for Brain and Behaviour and School of Social Sciences and Psychology, University of Western Sydney Sydney, NSW, Australia
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Structure, Distribution, and Function of Neuronal/Synaptic Spinules and Related Invaginating Projections. Neuromolecular Med 2015; 17:211-40. [PMID: 26007200 DOI: 10.1007/s12017-015-8358-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/08/2015] [Indexed: 10/23/2022]
Abstract
Neurons and especially their synapses often project long thin processes that can invaginate neighboring neuronal or glial cells. These "invaginating projections" can occur in almost any combination of postsynaptic, presynaptic, and glial processes. Invaginating projections provide a precise mechanism for one neuron to communicate or exchange material exclusively at a highly localized site on another neuron, e.g., to regulate synaptic plasticity. The best-known types are postsynaptic projections called "spinules" that invaginate into presynaptic terminals. Spinules seem to be most prevalent at large very active synapses. Here, we present a comprehensive review of all kinds of invaginating projections associated with both neurons in general and more specifically with synapses; we describe them in all animals including simple, basal metazoans. These structures may have evolved into more elaborate structures in some higher animal groups exhibiting greater synaptic plasticity. In addition to classic spinules and filopodial invaginations, we describe a variety of lesser-known structures such as amphid microvilli, spinules in giant mossy terminals and en marron/brush synapses, the highly specialized fish retinal spinules, the trophospongium, capitate projections, and fly gnarls, as well as examples in which the entire presynaptic or postsynaptic process is invaginated. These various invaginating projections have evolved to modify the function of a particular synapse, or to channel an effect to one specific synapse or neuron, without affecting those nearby. We discuss how they function in membrane recycling, nourishment, and cell signaling and explore how they might change in aging and disease.
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47
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Bernardinelli Y, Nikonenko I, Muller D. Structural plasticity: mechanisms and contribution to developmental psychiatric disorders. Front Neuroanat 2014; 8:123. [PMID: 25404897 PMCID: PMC4217507 DOI: 10.3389/fnana.2014.00123] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 10/14/2014] [Indexed: 01/31/2023] Open
Abstract
Synaptic plasticity mechanisms are usually discussed in terms of changes in synaptic strength. The capacity of excitatory synapses to rapidly modify the membrane expression of glutamate receptors in an activity-dependent manner plays a critical role in learning and memory processes by re-distributing activity within neuronal networks. Recent work has however also shown that functional plasticity properties are associated with a rewiring of synaptic connections and a selective stabilization of activated synapses. These structural aspects of plasticity have the potential to continuously modify the organization of synaptic networks and thereby introduce specificity in the wiring diagram of cortical circuits. Recent work has started to unravel some of the molecular mechanisms that underlie these properties of structural plasticity, highlighting an important role of signaling pathways that are also major candidates for contributing to developmental psychiatric disorders. We review here some of these recent advances and discuss the hypothesis that alterations of structural plasticity could represent a common mechanism contributing to the cognitive and functional defects observed in diseases such as intellectual disability, autism spectrum disorders and schizophrenia.
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Affiliation(s)
- Yann Bernardinelli
- Department of Basic Neurosciences, University of Geneva Medical School Geneva, Switzerland
| | - Irina Nikonenko
- Department of Basic Neurosciences, University of Geneva Medical School Geneva, Switzerland
| | - Dominique Muller
- Department of Basic Neurosciences, University of Geneva Medical School Geneva, Switzerland
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48
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Caroni P, Chowdhury A, Lahr M. Synapse rearrangements upon learning: from divergent-sparse connectivity to dedicated sub-circuits. Trends Neurosci 2014; 37:604-14. [PMID: 25257207 DOI: 10.1016/j.tins.2014.08.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/26/2014] [Accepted: 08/27/2014] [Indexed: 01/24/2023]
Abstract
Learning can involve formation of new synapses and loss of synapses, providing memory traces of learned skills. Recent findings suggest that these synapse rearrangements reflect assembly of task-related sub-circuits from initially broadly distributed and sparse connectivity in the brain. These local circuit remodeling processes involve rapid emergence of synapses upon learning, followed by protracted validation involving strengthening of some new synapses, and selective elimination of others. The timing of these consolidation processes can vary. Here, we review these findings, focusing on how molecular/cellular mechanisms of synapse assembly, strengthening, and elimination might interface with circuit/system mechanisms of learning and memory consolidation. An integrated understanding of these learning-related processes should provide a better basis to elucidate how experience, genetic background, and disease influence brain function.
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Affiliation(s)
- Pico Caroni
- Friedrich Miescher Institut, Basel, Switzerland.
| | | | - Maria Lahr
- Friedrich Miescher Institut, Basel, Switzerland
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49
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Paula-Lima AC, Adasme T, Hidalgo C. Contribution of Ca2+ release channels to hippocampal synaptic plasticity and spatial memory: potential redox modulation. Antioxid Redox Signal 2014; 21:892-914. [PMID: 24410659 DOI: 10.1089/ars.2013.5796] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
SIGNIFICANCE Memory is an essential human cognitive function. Consequently, to unravel the cellular and molecular mechanisms responsible for the synaptic plasticity events underlying memory formation, storage and loss represents a major challenge of present-day neuroscience. RECENT ADVANCES This review article first describes the wide-ranging functions played by intracellular Ca2+ signals in the activity-dependent synaptic plasticity processes underlying hippocampal spatial memory, and next, it focuses on how the endoplasmic reticulum Ca2+ release channels, the ryanodine receptors, and the inositol 1,4,5-trisphosphate receptors contribute to these processes. We present a detailed examination of recent evidence supporting the key role played by Ca2+ release channels in synaptic plasticity, including structural plasticity, and the formation/consolidation of spatial memory in the hippocampus. CRITICAL ISSUES Changes in cellular oxidative state particularly affect the function of Ca2+ release channels and alter hippocampal synaptic plasticity and the associated memory processes. Emphasis is placed in this review on how defective Ca2+ release, presumably due to increased levels of reactive oxygen species, may cause the hippocampal functional defects that are associated to aging and Alzheimer's disease (AD). FUTURE DIRECTIONS Additional studies should examine the precise molecular mechanisms by which Ca2+ release channels contribute to hippocampal synaptic plasticity and spatial memory formation/consolidation. Future studies should test whether redox-modified Ca2+ release channels contribute toward generating the intracellular Ca2+ signals required for sustained synaptic plasticity and hippocampal spatial memory, and whether loss of redox balance and oxidative stress, by altering Ca2+ release channel function, presumably contribute to the abnormal memory processes that occur during aging and AD.
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Affiliation(s)
- Andrea C Paula-Lima
- 1 Faculty of Dentistry, Institute for Research in Dental Sciences, Universidad de Chile , Santiago, Chile
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50
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Dotti CG, Esteban JA, Ledesma MD. Lipid dynamics at dendritic spines. Front Neuroanat 2014; 8:76. [PMID: 25152717 PMCID: PMC4126552 DOI: 10.3389/fnana.2014.00076] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 07/21/2014] [Indexed: 11/13/2022] Open
Abstract
Dynamic changes in the structure and composition of the membrane protrusions forming dendritic spines underlie memory and learning processes. In recent years a great effort has been made to characterize in detail the protein machinery that controls spine plasticity. However, we know much less about the involvement of lipids, despite being major membrane components and structure determinants. Moreover, protein complexes that regulate spine plasticity depend on specific interactions with membrane lipids for proper function and accurate intracellular signaling. In this review we gather information available on the lipid composition at dendritic spine membranes and on its dynamics. We pay particular attention to the influence that spine lipid dynamism has on glutamate receptors, which are key regulators of synaptic plasticity.
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