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Gasiorowska A, Wydrych M, Drapich P, Zadrozny M, Steczkowska M, Niewiadomski W, Niewiadomska G. The Biology and Pathobiology of Glutamatergic, Cholinergic, and Dopaminergic Signaling in the Aging Brain. Front Aging Neurosci 2021; 13:654931. [PMID: 34326765 PMCID: PMC8315271 DOI: 10.3389/fnagi.2021.654931] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022] Open
Abstract
The elderly population is growing worldwide, with important health and socioeconomic implications. Clinical and experimental studies on aging have uncovered numerous changes in the brain, such as decreased neurogenesis, increased synaptic defects, greater metabolic stress, and enhanced inflammation. These changes are associated with cognitive decline and neurobehavioral deficits. Although aging is not a disease, it is a significant risk factor for functional worsening, affective impairment, disease exaggeration, dementia, and general disease susceptibility. Conversely, life events related to mental stress and trauma can also lead to accelerated age-associated disorders and dementia. Here, we review human studies and studies on mice and rats, such as those modeling human neurodegenerative diseases, that have helped elucidate (1) the dynamics and mechanisms underlying the biological and pathological aging of the main projecting systems in the brain (glutamatergic, cholinergic, and dopaminergic) and (2) the effect of defective glutamatergic, cholinergic, and dopaminergic projection on disabilities associated with aging and neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. Detailed knowledge of the mechanisms of age-related diseases can be an important element in the development of effective ways of treatment. In this context, we briefly analyze which adverse changes associated with neurodegenerative diseases in the cholinergic, glutaminergic and dopaminergic systems could be targeted by therapeutic strategies developed as a result of our better understanding of these damaging mechanisms.
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Affiliation(s)
- Anna Gasiorowska
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Malgorzata Wydrych
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Patrycja Drapich
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Maciej Zadrozny
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Marta Steczkowska
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Wiktor Niewiadomski
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Grazyna Niewiadomska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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Overshooting Subcellular Redox-Responses in Rett-Mouse Hippocampus during Neurotransmitter Stimulation. Cells 2020; 9:cells9122539. [PMID: 33255426 PMCID: PMC7760232 DOI: 10.3390/cells9122539] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/16/2020] [Accepted: 11/22/2020] [Indexed: 12/21/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder associated with disturbed neuronal responsiveness and impaired neuronal network function. Furthermore, mitochondrial alterations and a weakened cellular redox-homeostasis are considered part of the complex pathogenesis. So far, overshooting redox-responses of MeCP2-deficient neurons were observed during oxidant-mediated stress, hypoxia and mitochondrial inhibition. To further clarify the relevance of the fragile redox-balance for the neuronal (dys)function in RTT, we addressed more physiological stimuli and quantified the subcellular redox responses to neurotransmitter-stimulation. The roGFP redox sensor was expressed in either the cytosol or the mitochondrial matrix of cultured mouse hippocampal neurons, and the responses to transient stimulation by glutamate, serotonin, dopamine and norepinephrine were characterized. Each neurotransmitter evoked more intense oxidizing responses in the cytosol of MeCP2-deficient than in wildtype neurons. In the mitochondrial matrix the neurotransmitter-evoked oxidizing changes were more moderate and more uniform among genotypes. This identifies the cytosol as an important reactive oxygen species (ROS) source and as less stably redox buffered. Fura-2 imaging and extracellular Ca2+ withdrawal confirmed cytosolic Ca2+ transients as a contributing factor of neurotransmitter-induced redox responses and their potentiation in the cytosol of MeCP2-deficient neurons. Chemical uncoupling demonstrated the involvement of mitochondria. Nevertheless, cytosolic NADPH- and xanthine oxidases interact to play the leading role in the neurotransmitter-mediated oxidizing responses. As exaggerated redox-responses were already evident in neonatal MeCP2-deficient neurons, they may contribute remarkably to the altered neuronal network performance and the disturbed neuronal signaling, which are among the hallmarks of RTT.
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Segal M. Dendritic spines: Morphological building blocks of memory. Neurobiol Learn Mem 2016; 138:3-9. [PMID: 27311757 DOI: 10.1016/j.nlm.2016.06.007] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/22/2016] [Accepted: 06/12/2016] [Indexed: 12/22/2022]
Abstract
The introduction of novel technologies, including high resolution time lapse imaging in behaving animals, molecular modification of the genome and optogenetic control of neuronal excitability have revolutionized the ability to detect subcellular changes in the brain, associated with learning and memory. The sequence of molecular cascades leading to formation, longevity and erasure of memories are being addressed in growing number of studies. Still, major issues concerning the relationship between the morphology and physiology of dendritic spines and memory mechanisms and the functional, neuronal network relevance of such parameters remain unsettled. The present review will summarize recent studies related to the immediate and long lasting changes in density, morphology and function of dendritic spines and their parent neurons following exposure to plasticity-producing stimulation in vivo and in vitro. Standing issues such as the relations between volume/shape and longevity, with respect to different classes of memories in different brain regions will be addressed. These studies indicate that the rules governing the structure/function relations of dendritic spines and memory in the brain are still not conclusive.
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Affiliation(s)
- Menahem Segal
- Department of Neurobiology, The Weizmann Institute, Rehovot 76100, Israel.
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From 2D to 3D: novel nanostructured scaffolds to investigate signalling in reconstructed neuronal networks. Sci Rep 2015; 5:9562. [PMID: 25910072 PMCID: PMC5407555 DOI: 10.1038/srep09562] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/10/2015] [Indexed: 12/21/2022] Open
Abstract
To recreate in vitro 3D neuronal circuits will ultimately increase the relevance of results from cultured to whole-brain networks and will promote enabling technologies for neuro-engineering applications. Here we fabricate novel elastomeric scaffolds able to instruct 3D growth of living primary neurons. Such systems allow investigating the emerging activity, in terms of calcium signals, of small clusters of neurons as a function of the interplay between the 2D or 3D architectures and network dynamics. We report the ability of 3D geometry to improve functional organization and synchronization in small neuronal assemblies. We propose a mathematical modelling of network dynamics that supports such a result. Entrapping carbon nanotubes in the scaffolds remarkably boosted synaptic activity, thus allowing for the first time to exploit nanomaterial/cell interfacing in 3D growth support. Our 3D system represents a simple and reliable construct, able to improve the complexity of current tissue culture models.
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Salas RE, Galea JM, Gamaldo AA, Gamaldo CE, Allen RP, Smith MT, Cantarero G, Lam BD, Celnik PA. Increased use-dependent plasticity in chronic insomnia. Sleep 2014; 37:535-44. [PMID: 24587576 DOI: 10.5665/sleep.3492] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES During normal sleep several neuroplasticity changes occur, some of which are considered to be fundamental to strengthen memories. Given the evidence linking sleep to neuroplasticity, it is conceivable that individuals with chronic sleep disruption, such as patients with chronic insomnia (CI), would experience abnormalities in neuroplastic processes during daytime. Protocols testing use-dependent plasticity (UDP), one of the mechanisms underlying formation of motor memories traces, provide a sensitive measure to assess neuroplasticity in the context of motor training. DESIGN AND PARTICIPANTS A well-established transcranial magnetic stimulation (TMS) paradigm was used to evaluate the ability of patients with CI and age-matched good sleeper controls to undergo UDP. We also investigated the effect of insomnia on intracortical motor excitability measures reflecting GABAergic and glutamatergic mechanisms. SETTING Human Brain Physiology Laboratory, Johns Hopkins Medical Institutions. MEASUREMENTS AND RESULTS We found that patients with CI experienced increased UDP changes relative to controls. This effect was not due to differences in motor training. In addition, patients with CI showed enhanced intracortical facilitation relative to controls, in the absence of changes in intracortical inhibitory measures. CONCLUSION This study provides the first evidence that patients with chronic insomnia have an increased plasticity response to physical exercise, possibly due to larger activation of glutamatergic mechanisms. This suggests a heightened state of neuroplasticity, which may reflect a form of maladaptive plasticity, similar to what has been described in dystonia patients and chronic phantom pain after amputation. These results could lead to development of novel treatments for chronic insomnia.
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Affiliation(s)
- Rachel E Salas
- Department of Neurology, Johns Hopkins Medical Institution, Baltimore, MD
| | - Joseph M Galea
- Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institution, Baltimore, MD
| | - Alyssa A Gamaldo
- School of Aging Studies, College of Behavioral & Community Sciences, University of South Florida, Tampa, FL
| | - Charlene E Gamaldo
- Department of Neurology, Johns Hopkins Medical Institution, Baltimore, MD
| | - Richard P Allen
- Department of Neurology, Johns Hopkins Medical Institution, Baltimore, MD
| | - Michael T Smith
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institution, Baltimore, MD
| | - Gabriela Cantarero
- Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institution, Baltimore, MD
| | - Barbara D Lam
- Department of Neurology, Johns Hopkins Medical Institution, Baltimore, MD
| | - Pablo A Celnik
- Department of Neurology, Johns Hopkins Medical Institution, Baltimore, MD ; Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institution, Baltimore, MD
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Sala C, Segal M. Dendritic spines: the locus of structural and functional plasticity. Physiol Rev 2014; 94:141-88. [PMID: 24382885 DOI: 10.1152/physrev.00012.2013] [Citation(s) in RCA: 338] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The introduction of high-resolution time lapse imaging and molecular biological tools has changed dramatically the rate of progress towards the understanding of the complex structure-function relations in synapses of central spiny neurons. Standing issues, including the sequence of molecular and structural processes leading to formation, morphological change, and longevity of dendritic spines, as well as the functions of dendritic spines in neurological/psychiatric diseases are being addressed in a growing number of recent studies. There are still unsettled issues with respect to spine formation and plasticity: Are spines formed first, followed by synapse formation, or are synapses formed first, followed by emergence of a spine? What are the immediate and long-lasting changes in spine properties following exposure to plasticity-producing stimulation? Is spine volume/shape indicative of its function? These and other issues are addressed in this review, which highlights the complexity of molecular pathways involved in regulation of spine structure and function, and which contributes to the understanding of central synaptic interactions in health and disease.
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Aoshima Y, Hokama R, Sou K, Sarker SR, Iida K, Nakamura H, Inoue T, Takeoka S. Cationic amino acid based lipids as effective nonviral gene delivery vectors for primary cultured neurons. ACS Chem Neurosci 2013; 4:1514-9. [PMID: 24087930 PMCID: PMC3867963 DOI: 10.1021/cn400036j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The delivery of specific genes into neurons offers a potent approach for treatment of diseases as well as for the study of neuronal cell biology. Here we investigated the capabilities of cationic amino acid based lipid assemblies to act as nonviral gene delivery vectors in primary cultured neurons. An arginine-based lipid, Arg-C3-Glu2C14, and a lysine-based lipid, Lys-C3-Glu2C14, with two different types of counterion, chloride ion (Cl-) and trifluoroacetic acid (TFA-), were shown to successfully mediate transfection of primary cultured neurons with plasmid DNA encoding green fluorescent protein. Among four types of lipids, we optimized their conditions such as the lipid-to-DNA ratio and the amount of pDNA and conducted a cytotoxicity assay at the same time. Overall, Arg-C3-Glu2C14 with TFA- induced a rate of transfection in primary cultured neurons higher than that of Lys-C3-Glu2C14 using an optimal weight ratio of lipid-to-plasmid DNA of 1. Moreover, it was suggested that Arg-C3-Glu2C14 with TFA- showed the optimized value higher than that of Lipofectamine2000 in experimental conditions. Thus, Arg-C3-Glu2C14 with TFA- is a promising candidate as a reliable transfection reagent for primary cultured neurons with a relatively low cytotoxicity.
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Affiliation(s)
- Yumiko Aoshima
- Department of Life Science
and Medical Bioscience, Graduate School of
Advanced Science and Engineering, Waseda
University (TWIns), 2-2 Wakamatsu-cho,
Shinjuku-ku, Tokyo 162-8480, Japan
| | - Ryosuke Hokama
- Department of Life Science
and Medical Bioscience, Graduate School of
Advanced Science and Engineering, Waseda
University (TWIns), 2-2 Wakamatsu-cho,
Shinjuku-ku, Tokyo 162-8480, Japan
| | - Keitaro Sou
- Department of Life Science
and Medical Bioscience, Graduate School of
Advanced Science and Engineering, Waseda
University (TWIns), 2-2 Wakamatsu-cho,
Shinjuku-ku, Tokyo 162-8480, Japan
| | - Satya Ranjan Sarker
- Department of Life Science
and Medical Bioscience, Graduate School of
Advanced Science and Engineering, Waseda
University (TWIns), 2-2 Wakamatsu-cho,
Shinjuku-ku, Tokyo 162-8480, Japan
| | - Kabuto Iida
- Department of Life Science
and Medical Bioscience, Graduate School of
Advanced Science and Engineering, Waseda
University (TWIns), 2-2 Wakamatsu-cho,
Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hideki Nakamura
- Department of Life Science
and Medical Bioscience, Graduate School of
Advanced Science and Engineering, Waseda
University (TWIns), 2-2 Wakamatsu-cho,
Shinjuku-ku, Tokyo 162-8480, Japan
| | - Takafumi Inoue
- Department of Life Science
and Medical Bioscience, Graduate School of
Advanced Science and Engineering, Waseda
University (TWIns), 2-2 Wakamatsu-cho,
Shinjuku-ku, Tokyo 162-8480, Japan
| | - Shinji Takeoka
- Department of Life Science
and Medical Bioscience, Graduate School of
Advanced Science and Engineering, Waseda
University (TWIns), 2-2 Wakamatsu-cho,
Shinjuku-ku, Tokyo 162-8480, Japan
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Segal M. Dendritic spines, synaptic plasticity and neuronal survival: activity shapes dendritic spines to enhance neuronal viability. Eur J Neurosci 2010; 31:2178-84. [PMID: 20550565 DOI: 10.1111/j.1460-9568.2010.07270.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An emerging view of structure-function relations of synapses in central spiny neurons asserts that larger spines produce large synaptic currents and that these large spines are persistent ('memory') compared to small spines which are transient. Furthermore, 'learning' involves enlargement of small spine heads and their conversion to being large and stable. It is also assumed that the number of spines, hence the number of synapses, is reflected in the frequency of miniature excitatory postsynaptic currents (mEPSCs). Consequently, there is an assumption that the size and number of mEPSCs are closely correlated with, respectively, the physical size of synapses and number of spines. However, several recent observations do not conform to these generalizations, necessitating a reassessment of the model: spine dimension and synaptic responses are not always correlated. It is proposed that spines are formed and shaped by ongoing network activity, not necessarily by a 'learning' event, to the extent that, in the absence of such activity, new spines are not formed and existing ones disappear or convert into thin filopodia. In the absence of spines, neurons can still maintain synapses with afferent fibers, which can now terminate on its dendritic shaft. Shaft synapses are likely to produce larger synaptic currents than spine synapses. Following loss of their spines, neurons are less able to cope with the large synaptic inputs impinging on their dendritic shafts, and these inputs may lead to their eventual death. Thus, dendritic spines protect neurons from synaptic activity-induced rises in intracellular calcium concentrations.
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Affiliation(s)
- Menahem Segal
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel.
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Rapid and long-lasting increase in sites for synapse assembly during late-phase potentiation in rat hippocampal neurons. PLoS One 2009; 4:e7690. [PMID: 19893634 PMCID: PMC2767506 DOI: 10.1371/journal.pone.0007690] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 10/12/2009] [Indexed: 01/07/2023] Open
Abstract
Long-term potentiation in hippocampal neurons has stages that correspond to the stages of learning and memory. Early-phase (10–30 min) potentiation is accompanied by rapid increases in clusters or puncta of presynaptic and postsynaptic proteins, which depend on actin polymerization but not on protein synthesis. We have now examined changes in pre- and postsynaptic puncta and structures during glutamate-induced late-phase (3 hr) potentiation in cultured hippocampal neurons. We find that (1) the potentiation is accompanied by long-lasting maintenance of the increases in puncta, which depends on protein synthesis, (2) most of the puncta and synaptic structures are very dynamic, continually assembling and disassembling at sites that are more stable than the puncta or structures themselves, (3) the increase in presynaptic puncta appears to be due to both rapid and more gradual increases in the number of sites where the puncta may form, and also to the stabilization of existing puncta, (4) under control conditions, puncta of postsynaptic proteins behave similarly to puncta of presynaptic proteins and share sites with them, and (5) the increase in presynaptic puncta is accompanied by a similar increase in presumably presynaptic structures, which may form at distinct as well as shared sites. The new sites could contribute to the transition between the early and late phase mechanisms of plasticity by serving as seeds for the formation and maintenance of new synapses, thus acting as local “tags” for protein synthesis-dependent synaptic growth during late-phase plasticity.
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Marquez de la Plata CD, Hart T, Hammond FM, Frol AB, Hudak A, Harper CR, O'Neil-Pirozzi TM, Whyte J, Carlile M, Diaz-Arrastia R. Impact of age on long-term recovery from traumatic brain injury. Arch Phys Med Rehabil 2008; 89:896-903. [PMID: 18452739 DOI: 10.1016/j.apmr.2007.12.030] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 12/18/2007] [Accepted: 12/26/2007] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To determine whether older persons are at increased risk for progressive functional decline after traumatic brain injury (TBI). DESIGN Longitudinal cohort study. SETTING Traumatic Brain Injury Model Systems (TBIMS) rehabilitation centers. PARTICIPANTS Subjects enrolled in the TBIMS national dataset. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Disability Rating Scale (DRS), FIM instrument cognitive items, and the Glasgow Outcome Scale-Extended. RESULTS Participants were separated into 3 age tertiles: youngest (16-26y), intermediate (27-39y), and oldest (> or =40y). DRS scores were comparable across age groups at admission to a rehabilitation center. The oldest group was slightly more disabled at discharge from rehabilitation despite having less severe acute injury severity than the younger groups. Although DRS scores for the 2 younger groups improved significantly from year 1 to year 5, the greatest magnitude of improvement in disability was seen among the youngest group. In addition, after dividing patients into groups according to whether their DRS scores improved (13%), declined (10%), or remained stable (77%) over time, the likelihood of decline was found to be greater for the 2 older groups than for the youngest group. A multiple regression model showed that age has a significant negative influence on DRS score 5 years post-TBI after accounting for the effects of covariates. CONCLUSIONS This study supported our primary hypothesis that older patients show greater decline over the first 5 years after TBI than younger patients. In addition, the greatest amount of improvement in disability was observed among the youngest group of survivors. These results suggest that TBI survivors, especially older patients, may be candidates for neuroprotective therapies after TBI.
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