1
|
Navakkode S, Kennedy BK. Neural ageing and synaptic plasticity: prioritizing brain health in healthy longevity. Front Aging Neurosci 2024; 16:1428244. [PMID: 39161341 PMCID: PMC11330810 DOI: 10.3389/fnagi.2024.1428244] [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: 05/06/2024] [Accepted: 07/24/2024] [Indexed: 08/21/2024] Open
Abstract
Ageing is characterized by a gradual decline in the efficiency of physiological functions and increased vulnerability to diseases. Ageing affects the entire body, including physical, mental, and social well-being, but its impact on the brain and cognition can have a particularly significant effect on an individual's overall quality of life. Therefore, enhancing lifespan and physical health in longevity studies will be incomplete if cognitive ageing is over looked. Promoting successful cognitive ageing encompasses the objectives of mitigating cognitive decline, as well as simultaneously enhancing brain function and cognitive reserve. Studies in both humans and animal models indicate that cognitive decline related to normal ageing and age-associated brain disorders are more likely linked to changes in synaptic connections that form the basis of learning and memory. This activity-dependent synaptic plasticity reorganises the structure and function of neurons not only to adapt to new environments, but also to remain robust and stable over time. Therefore, understanding the neural mechanisms that are responsible for age-related cognitive decline becomes increasingly important. In this review, we explore the multifaceted aspects of healthy brain ageing with emphasis on synaptic plasticity, its adaptive mechanisms and the various factors affecting the decline in cognitive functions during ageing. We will also explore the dynamic brain and neuroplasticity, and the role of lifestyle in shaping neuronal plasticity.
Collapse
Affiliation(s)
- Sheeja Navakkode
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, Centre for Healthy Longevity, National University Health System, National University of Singapore, Singapore, Singapore
- Life Sciences Institute Neurobiology Programme, Centre for Life Sciences, National University of Singapore, Singapore, Singapore
| | - Brian K. Kennedy
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, Centre for Healthy Longevity, National University Health System, National University of Singapore, Singapore, Singapore
- Life Sciences Institute Neurobiology Programme, Centre for Life Sciences, National University of Singapore, Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Departments of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Buck Institute for Research on Ageing, Novato, CA, United States
| |
Collapse
|
2
|
Gramuntell Y, Klimczak P, Coviello S, Perez-Rando M, Nacher J. Effects of Aging on the Structure and Expression of NMDA Receptors of Somatostatin Expressing Neurons in the Mouse Hippocampus. Front Aging Neurosci 2022; 13:782737. [PMID: 35002680 PMCID: PMC8733323 DOI: 10.3389/fnagi.2021.782737] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/23/2021] [Indexed: 11/13/2022] Open
Abstract
Changes in the physiology, neurochemistry and structure of neurons, particularly of their dendritic spines, are thought to be crucial players in age-related cognitive decline. One of the most studied brain structures affected by aging is the hippocampus, known to be involved in different essential cognitive processes. While the aging-associated quantitative changes in dendritic spines of hippocampal pyramidal cells have already been studied, the relationship between aging and the structural dynamics of hippocampal interneurons remains relatively unknown. Spines are not a frequent feature in cortical inhibitory neurons, but these postsynaptic structures are abundant in a subpopulation of somatostatin expressing interneurons, particularly in oriens-lacunosum moleculare (O-LM) cells in the hippocampal CA1. Previous studies from our laboratory have shown that the spines of these interneurons are highly plastic and influenced by NMDA receptor manipulation. Thus, in the present study, we have investigated the impact of aging on this interneuronal subpopulation. The analyses were performed in 3−, 9−, and 16-month-old GIN mice, a strain in which somatostatin positive interneurons express GFP. We studied the changes in the density of dendritic spines, en passant boutons, and the expression of NMDA receptors (GluN1 and GluN2B) using confocal microscopy and image analysis. We observed a significant decrease in dendritic spine density in 9-month-old animals when compared with 3-month-old animals. We also observed a decrease in the expression of the GluN2B subunit in O-LM cells, but not of that of GluN1, during aging. These results will constitute the basis for more advanced studies of the structure and connectivity of interneurons during aging and their contribution to cognitive decline.
Collapse
Affiliation(s)
- Yaiza Gramuntell
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain
| | - Patrycja Klimczak
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Simona Coviello
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain
| | - Marta Perez-Rando
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.,Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
| | - Juan Nacher
- Neurobiology Unit, Program in Neurosciences and Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain.,Spanish National Network for Research in Mental Health, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.,Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain
| |
Collapse
|
3
|
Blum K, Gold MS, Llanos-Gomez L, Jalali R, Thanos PK, Bowirrat A, Downs WB, Bagchi D, Braverman ER, Baron D, Roy AK, Badgaiyan RD. Hypothesizing Nutrigenomic-Based Precision Anti-Obesity Treatment and Prophylaxis: Should We Be Targeting Sarcopenia Induced Brain Dysfunction? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18189774. [PMID: 34574696 PMCID: PMC8470221 DOI: 10.3390/ijerph18189774] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 12/15/2022]
Abstract
Background: The United States Centers for Disease Control and Prevention (CDC) estimates a total obesity rate of 30% for 12 states and a 20% obesity rate nationwide. The obesity epidemic continues to increase in spite of preventative measures undertaken worldwide. Pharmacological treatments promise to reduce total fat mass. However, medications may have significant side effects and can be potentially fatal. Data Retrieval: This brief review, based on a PUBMED search of the key terms "Obesity" and" Sarcopenia," will present evidence to corroborate the existence of Reward Deficiency Syndrome (RDS) in obesity and the involvement of catecholaminergic pathways in substance seeking behavior, particularly as it relates to carbohydrates cravings. Expert Opinion: The genetic basis and future genetic testing of children for risk of aberrant generalized craving behavior are considered a prevention method. Here we present evidence supporting the use of precursor amino acid therapy and modulation of enkephalinase, MOA, and COMT inhibition in key brain regions. Such treatments manifest in improved levels of dopamine/norepinephrine, GABA, serotonin, and enkephalins. We also present evidence substantiating insulin sensitivity enhancement via Chromium salts, which affect dopamine neuronal synthesis regulation. We believe our unique combination of natural ingredients will influence many pathways leading to the promotion of well-being and normal healthy metabolic functioning. Sarcopenia has been shown to reduce angiogenesis and possible cerebral blood flow. Exercise seems to provide a significant benefit to overcome this obesity-promoting loss of muscle density. Conclusion: Utilization of proposed nutrigenomic formulae based on coupling genetic obesity risk testing promotes generalized anti-craving of carbohydrates and can inhibit carbohydrate bingeing, inducing significant healthy fat loss and relapse prevention.
Collapse
Affiliation(s)
- Kenneth Blum
- Center for Psychiatry, Medicine & Primary Care (Office of the Provost), Division of Addiction Research & Education, Western University Health Science, Pomona, CA 91766, USA;
- Institute of Psychology, ELTE Eötvös Loránd University, Kazinczy u. 23-27, 1075 Budapest, Hungary
- Division of Nutrigenomics, Genomic Testing Center Geneus Health, San Antonio, TX 78249, USA
- Department of Psychiatry, University of Vermont, Burlington, VT 05401, USA
- Department of Psychiatry, Wright University Boonshoff School of Medicine, Dayton, OH 45377, USA
- Division of Precision Nutrition, Victory Nutrition International, Bonita Springs, FL 34135, USA; (W.B.D.); (D.B.)
- The Kenneth Blum Behavioral & Neurogenetic Institute, Division of Ivitalize Inc., Austin, TX 78701, USA; (L.L.-G.); (R.J.)
- Division of Clinical Neurology, Path Foundation NY, New York, NY 10010, USA;
- Correspondence:
| | - Mark S. Gold
- Department of Psychiatry, School of Medicine, Tulane University, New Orleans, LA 70118, USA; (M.S.G.); (A.K.R.III)
| | - Luis Llanos-Gomez
- The Kenneth Blum Behavioral & Neurogenetic Institute, Division of Ivitalize Inc., Austin, TX 78701, USA; (L.L.-G.); (R.J.)
| | - Rehan Jalali
- The Kenneth Blum Behavioral & Neurogenetic Institute, Division of Ivitalize Inc., Austin, TX 78701, USA; (L.L.-G.); (R.J.)
| | - Panayotis K. Thanos
- Department of Psychology & Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions (BNNLA), Research Institute on Addictions, University at Buffalo, Buffalo, NY 14260, USA;
| | - Abdalla Bowirrat
- Department of Molecular Biology, Adelson School of Medicine, Ariel University, Ariel 40700, Israel;
| | - William B. Downs
- Division of Precision Nutrition, Victory Nutrition International, Bonita Springs, FL 34135, USA; (W.B.D.); (D.B.)
| | - Debasis Bagchi
- Division of Precision Nutrition, Victory Nutrition International, Bonita Springs, FL 34135, USA; (W.B.D.); (D.B.)
- Department of Pharmaceutical Sciences, College of Pharmacy & Health Sciences, Texas Southern University, Houston, TX 77004, USA
| | - Eric R. Braverman
- Division of Clinical Neurology, Path Foundation NY, New York, NY 10010, USA;
| | - David Baron
- Center for Psychiatry, Medicine & Primary Care (Office of the Provost), Division of Addiction Research & Education, Western University Health Science, Pomona, CA 91766, USA;
| | - Alphonso Kenison Roy
- Department of Psychiatry, School of Medicine, Tulane University, New Orleans, LA 70118, USA; (M.S.G.); (A.K.R.III)
| | - Rajendra D. Badgaiyan
- Department of Psychiatry, South Texas Veteran Health Care System, Audie L. Murphy Memorial VA Hospital, Long School of Medicine, University of Texas Medical Center, San Antonio, TX 78249, USA;
| |
Collapse
|
4
|
The Beneficial Effects of Cognitive Walking Program on Improving Cognitive Function and Physical Fitness in Older Adults. Healthcare (Basel) 2021; 9:healthcare9040419. [PMID: 33916351 PMCID: PMC8066196 DOI: 10.3390/healthcare9040419] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 03/29/2021] [Accepted: 04/02/2021] [Indexed: 11/21/2022] Open
Abstract
Exercise and cognitive training can improve the brain-related health of the elderly. We investigated the effects of a cognitive walking program (CWP) involving simultaneous performance of indoor walking and cognitive training on cognitive function and physical fitness compared to normal walking (NW) outdoors. Participants were grouped according to whether they performed regular exercise for at least 3 months prior to the participation in this study. Active participants were assigned to the CWP-active group (CWPAG). Sedentary participants were randomly assigned to the CWP (CWPSG) or NW group (NWSG). CWP and NW were performed for 60 min, 3 times a week, for 6 months. Cognitive function (attention, visuospatial function, memory, and frontal/executive function) and physical fitness (cardiorespiratory fitness, lower extremity muscular strength, and active balance ability) were measured at baseline, 3 months, and 6 months after the program onset. Cognitive function showed improvements over time in all three groups, especially in CWPAG. No clear difference was observed between CWPSG and NWSG. Improvements in all fitness measures were also observed in all three groups. These findings collectively indicate the beneficial effects of CWP, as well as NW, on improving cognitive function and physical fitness in older adults, especially those who are physically active.
Collapse
|
5
|
Orock A, Logan S, Deak F. Age-Related Cognitive Impairment: Role of Reduced Synaptobrevin-2 Levels in Deficits of Memory and Synaptic Plasticity. J Gerontol A Biol Sci Med Sci 2021; 75:1624-1632. [PMID: 30649208 DOI: 10.1093/gerona/glz013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Indexed: 01/02/2023] Open
Abstract
Cognitive impairment in the aging population is quickly becoming a health care priority, for which currently no disease-modifying treatment is available. Multiple domains of cognition decline with age even in the absence of neurodegenerative diseases. The cellular and molecular changes leading to cognitive decline with age remain elusive. Synaptobrevin-2 (Syb2), the major vesicular SNAP receptor protein, highly expressed in the cerebral cortex and hippocampus, is essential for synaptic transmission. We have analyzed Syb2 protein levels in mice and found a decrease with age. To investigate the functional consequences of lower Syb2 expression, we have used adult Syb2 heterozygous mice (Syb2+/-) with reduced Syb2 levels. This allowed us to mimic the age-related decrease of Syb2 in the brain in order to selectively test its effects on learning and memory. Our results show that Syb2+/- animals have impaired learning and memory skills and they perform worse with age in the radial arm water maze assay. Syb2+/- hippocampal neurons have reduced synaptic plasticity with reduced release probability and impaired long-term potentiation in the CA1 region. Syb2+/- neurons also have lower vesicular release rates when compared to WT controls. These results indicate that reduced Syb2 expression with age is sufficient to cause cognitive impairment.
Collapse
Affiliation(s)
- Albert Orock
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Sreemathi Logan
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Ferenc Deak
- Oklahoma Center for Neuroscience, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, Reynolds Oklahoma Center on Aging, Oklahoma City.,Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City.,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City.,Department of Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City
| |
Collapse
|
6
|
Charousaei A, Nasehi M, Babapour V, Vaseghi S, Zarrindast MR. The effect of 5-HT 4 serotonin receptors in the CA3 hippocampal region on D-AP5-induced anxiolytic-like effects: Isobolographic analyses. Behav Brain Res 2020; 397:112933. [PMID: 32991927 DOI: 10.1016/j.bbr.2020.112933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/25/2020] [Accepted: 09/22/2020] [Indexed: 01/03/2023]
Abstract
Increasing evidence shows the close relationship between hippocampal glutamatergic and serotonergic systems through the modulation of behavioral responses. This study aimed to investigate the possible involvement of 5-HT4 receptors in the CA3 hippocampal region in anxiolytic-like effects induced by D-AP5 (a competitive antagonist of the glutamate NMDA [N-Methyl-D-aspartate] receptor). Male Wistar rats were placed in the elevated plus maze (EPM) apparatus that is used to assess anxiety-related behaviors, and the percentages of open arm time (%OAT) and open arm entries (%OAE) which are associated with anxiety-related behaviors were measured. The close arm entries (CAE) which is correlated with locomotor activity was also evaluated. The results showed that, intra-CA3 injection of D-AP5 (0.4 μg/rat), RS67333 (1.2 μg/rat; a 5-HT4 receptor agonist), and RS23597-190 (1.2 μg/rat; a 5-HT4 receptor antagonist) increased %OAT and %OAE, indicating the anxiolytic-like effect of these drugs. Also, only RS23597-190 (1.2 μg/rat) decreased CAE. Intra-CA3 injection of sub-threshold dose of RS67333 (0.012 μg/rat) or RS23597-190 (0.012 μg/rat), 5 min before the injection of D-AP5 (0.2 μg/rat) increased %OAT, indicating potentiating the anxiolytic-like effect of D-AP5. The isobolographic analyses also showed the additive or synergistic anxiolytic-like effect of intra-CA3 co-administration of D-AP5 with RS67333 or RS23597-190, respectively. In conclusion, CA3 5-HT4 receptors are involved in D-AP5-induced anxiolytic-like behaviors in rats.
Collapse
Affiliation(s)
- Amin Charousaei
- Department of Physiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Mohammad Nasehi
- Cognitive and Neuroscience Research Center (CNRC), Amir-Almomenin Hospital, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
| | - Vahab Babapour
- Department of Physiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Salar Vaseghi
- Cognitive and Neuroscience Research Center (CNRC), Amir-Almomenin Hospital, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran; Department of Cognitive Neuroscience, Institute for Cognitive Science Studies (ICSS), Tehran, Iran
| | - Mohammad-Reza Zarrindast
- Department of Cognitive Neuroscience, Institute for Cognitive Science Studies (ICSS), Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Neuroendocrinology, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
7
|
Kumar A. Calcium Signaling During Brain Aging and Its Influence on the Hippocampal Synaptic Plasticity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:985-1012. [PMID: 31646542 DOI: 10.1007/978-3-030-12457-1_39] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Calcium (Ca2+) ions are highly versatile intracellular signaling molecules and are universal second messenger for regulating a variety of cellular and physiological functions including synaptic plasticity. Ca2+ homeostasis in the central nervous system endures subtle dysregulation with advancing age. Research has provided abundant evidence that brain aging is associated with altered neuronal Ca2+ regulation and synaptic plasticity mechanisms. Much of the work has focused on the hippocampus, a brain region critically involved in learning and memory, which is particularly susceptible to dysfunction during aging. The current chapter takes a specific perspective, assessing various Ca2+ sources and the influence of aging on Ca2+ sources and synaptic plasticity in the hippocampus. Integrating the knowledge of the complexity of age-related alterations in neuronal Ca2+ signaling and synaptic plasticity mechanisms will positively shape the development of highly effective therapeutics to treat brain disorders including cognitive impairment associated with aging and neurodegenerative disease.
Collapse
Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
| |
Collapse
|
8
|
Doguc DK, Deniz F, İlhan İ, Ergonul E, Gultekin F. Prenatal exposure to artificial food colorings alters NMDA receptor subunit concentrations in rat hippocampus. Nutr Neurosci 2019; 24:784-794. [PMID: 31679476 DOI: 10.1080/1028415x.2019.1681065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Exposure to artificial food color additives (AFCAs) has been implicated in the etiology of certain childhood hyperactivity and learning disabilities. N-methyl-D-aspartate receptors and alpha-7 nicotinic acetylcholine receptor (α7 nAChR) are involved in learning and memory. We administered a mixture of AFCAs (erythrosine, ponceau 4R, allura red AC, sunset yellow FCF, tartrazine, amaranth, brilliant blue, azorubine, and indigotine) to female rats during gestation to investigate the effects of prenatal exposure to AFCAs on neurobehavior, spatial learning, and memory in their offspring. We also investigated whether AFCAs modulate NR2A, NR2B, and α7 nAChR protein levels in their offsprings' hippocampi. Although spatial learning and memory were not altered, the offspring of rats exposed to AFCAs exhibited decreased motivation and increased despair-related behavior. NR2A and NR2B protein levels were significantly reduced in female offspring in the experimental group (p < 0.05), whereas α7 nAChR level was not significantly altered. Our results suggest that prenatal exposure to AFCAs may lead to sex-dependent alterations in glutamatergic signaling which may continue into adolescence.
Collapse
Affiliation(s)
- Duygu Kumbul Doguc
- Department of Medical Biochemistry, Medical School, Suleyman Demirel University, Isparta, Turkey
| | - Firdevs Deniz
- Medical Biochemistry Laboratory, Atatürk Government Hospital, Antalya, Turkey
| | - İlter İlhan
- Department of Medical Biochemistry, Medical School, Suleyman Demirel University, Isparta, Turkey
| | - Esin Ergonul
- Department of Medical Education, Medical School, Dokuz Eylul University, İzmir, Turkey
| | - Fatih Gultekin
- Department of Medical Biochemistry, School of Medicine, University of Health Sciences, İstanbul, Turkey
| |
Collapse
|
9
|
Brivio P, Paladini MS, Racagni G, Riva MA, Calabrese F, Molteni R. From Healthy Aging to Frailty: In Search of the Underlying Mechanisms. Curr Med Chem 2019; 26:3685-3701. [PMID: 31333079 DOI: 10.2174/0929867326666190717152739] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/14/2018] [Accepted: 03/08/2019] [Indexed: 11/22/2022]
Abstract
Population aging is accelerating rapidly worldwide, from 461 million people older than 65 years in 2004 to an estimated 2 billion people by 2050, leading to critical implications for the planning and delivery of health and social care. The most problematic expression of population aging is the clinical condition of frailty, which is a state of increased vulnerability that develops as a consequence of the accumulation of microscopic damages in many physiological systems that lead to a striking and disproportionate change in health state, even after an apparently small insult. Since little is known about the biology of frailty, an important perspective to understand this phenomenon is to establish how the alterations that physiologically occur during a condition of healthy aging may instead promote cumulative decline with subsequent depletion of homoeostatic reserve and increase the vulnerability also after minor stressor events. In this context, the present review aims to provide a description of the molecular mechanisms that, by having a critical impact on behavior and neuronal function in aging, might be relevant for the development of frailty. Moreover, since these biological systems are also involved in the coping strategies set in motion to respond to environmental challenges, we propose a role for lifestyle stress as an important player to drive frailty in aging.
Collapse
Affiliation(s)
- Paola Brivio
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Maria Serena Paladini
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Giorgio Racagni
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy.,Associazione di Psicofarmacologia, Milan, Italy
| | - Marco Andrea Riva
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Francesca Calabrese
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Raffaella Molteni
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| |
Collapse
|
10
|
Acute and Chronic Sleep Deprivation-Related Changes in N-methyl-D-aspartate Receptor-Nitric Oxide Signalling in the Rat Cerebral Cortex with Reference to Aging and Brain Lateralization. Int J Mol Sci 2019; 20:ijms20133273. [PMID: 31277281 PMCID: PMC6651230 DOI: 10.3390/ijms20133273] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/13/2019] [Accepted: 06/27/2019] [Indexed: 12/12/2022] Open
Abstract
Aging and chronic sleep deprivation (SD) are well-recognized risk factors for Alzheimer’s disease (AD), with N-methyl-D-aspartate receptor (NMDA) and downstream nitric oxide (NO) signalling implicated in the process. Herein, we investigate the impact of the age- and acute or chronic SD-dependent changes on the expression of NMDA receptor subunits (NR1, NR2A, and NR2B) and on the activities of NO synthase (NOS) isoforms in the cortex of Wistar rats, with reference to cerebral lateralization. In young adult controls, somewhat lateralized seasonal variations in neuronal and endothelial NOS have been observed. In aged rats, overall decreases in NR1, NR2A, and NR2B expression and reduction in neuronal and endothelial NOS activities were found. The age-dependent changes in NR1 and NR2B significantly correlated with neuronal NOS in both hemispheres. Changes evoked by chronic SD (dysfunction of endothelial NOS and the increasing role of NR2A) differed from those evoked by acute SD (increase in inducible NOS in the right side). Collectively, these results demonstrate age-dependent regulation of the level of NMDA receptor subunits and downstream NOS isoforms throughout the rat brain, which could be partly mimicked by SD. As described herein, age and SD alterations in the prevalence of NMDA receptors and NOS could contribute towards cognitive decline in the elderly, as well as in the pathobiology of AD and the neurodegenerative process.
Collapse
|
11
|
Chandran R, Kumar M, Kesavan L, Jacob RS, Gunasekaran S, Lakshmi S, Sadasivan C, Omkumar R. Cellular calcium signaling in the aging brain. J Chem Neuroanat 2019; 95:95-114. [DOI: 10.1016/j.jchemneu.2017.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/03/2017] [Accepted: 11/07/2017] [Indexed: 12/21/2022]
|
12
|
Gaynor LS, Johnson SA, Mizell JM, Campos KT, Maurer AP, Bauer RM, Burke SN. Impaired discrimination with intact crossmodal association in aged rats: A dissociation of perirhinal cortical-dependent behaviors. Behav Neurosci 2018; 132:138-151. [PMID: 29809042 PMCID: PMC5975639 DOI: 10.1037/bne0000246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The perirhinal cortex (PRC) supports associative memory and perception, and PRC dysfunction impairs animals' abilities to associate stimulus features across sensory modalities. PRC damage also leads to deficits in discriminating between stimuli that share features. Although PRC-dependent stimulus discrimination has been shown to be impaired with advanced age, data regarding the abilities of older adults and other animals to form PRC-dependent associations have been equivocal. Moreover, the extent to which similar neural computations within the PRC support associative memory versus discrimination abilities have not been directly examined. In the current study, young and aged rats were cross-characterized on two PRC-dependent crossmodal object recognition (CMOR) tasks to test associative memory, and a LEGO object discrimination task. In the CMOR tasks, rats were familiarized with an object with access to tactile input and then tested for recognition with visual input only. The relative exploration time of novel versus familiar objects indicated that aged rats showed preference for the novel over familiar object with and without an epoch of multimodal preexposure to the familiar object prior to the testing session. Furthermore, crossmodal recognition performance between young and aged rats was not significantly different. In contrast, for the LEGO object discrimination task, aged rats were impaired relative to young rats. Notably, aged rats that performed poorly on the LEGO object discrimination task had better performance on the CMOR tasks. The dissociation of discrimination and association abilities with age suggests that these behaviors rely on distinct neural computations within PRC-medial temporal lobe circuit. (PsycINFO Database Record
Collapse
Affiliation(s)
| | | | | | | | | | - Russell M Bauer
- Department of Clinical and Health Psychology, University of Florida
| | | |
Collapse
|
13
|
Kumar A, Foster TC. Alteration in NMDA Receptor Mediated Glutamatergic Neurotransmission in the Hippocampus During Senescence. Neurochem Res 2018; 44:38-48. [PMID: 30209673 DOI: 10.1007/s11064-018-2634-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 09/07/2018] [Accepted: 09/08/2018] [Indexed: 12/17/2022]
Abstract
Glutamate is the primary excitatory neurotransmitter in neurons and glia. N-methyl-D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and kainate receptors are major ionotropic glutamate receptors. Glutamatergic neurotransmission is strongly linked with Ca2+ homeostasis. Research has provided ample evidence that brain aging is associated with altered glutamatergic neurotransmission and Ca2+ dysregulation. Much of the work has focused on the hippocampus, a brain region critically involved in learning and memory, which is particularly susceptible to dysfunction during senescence. The current review examines Ca2+ regulation with a focus on the NMDA receptors in the hippocampus. Integrating the knowledge of the complexity of age-related alterations in Ca2+ homeostasis and NMDA receptor-mediated glutamatergic neurotransmission will positively shape the development of highly effective therapeutics to treat brain disorders including cognitive impairment.
Collapse
Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, PO Box 100244, Gainesville, FL, 32610-0244, USA.
| | - Thomas C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, PO Box 100244, Gainesville, FL, 32610-0244, USA.
- Genetics and Genomics Program, University of Florida, Gainesville, FL, 32611, USA.
| |
Collapse
|
14
|
Permpoonputtana K, Tangweerasing P, Mukda S, Boontem P, Nopparat C, Govitrapong P. Long-term administration of melatonin attenuates neuroinflammation in the aged mouse brain. EXCLI JOURNAL 2018; 17:634-646. [PMID: 30108467 PMCID: PMC6088215 DOI: 10.17179/excli2017-654] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 06/11/2018] [Indexed: 01/08/2023]
Abstract
Aging is often accompanied by a decline in cognitive function in conjunction with a variety of neurobiological changes, including neuroinflammation. Melatonin is a key endogenous indoleamine secreted by the pineal gland that plays a crucial role in the regulation of circadian rhythms, is a potent free radical scavenger, has anti-inflammatory activity and serves numerous other functions. However, the role of melatonin in sterile inflammation in the brain has not been fully investigated. In the present study, we investigated the neuroinflammation status in aged mouse brains. The results showed that the protein levels of integrin αM (CD11b), glial fibrillary acidic protein (GFAP), the major pro-inflammatory cytokines (interleukin-1 beta [IL-1β], interleukin-6 [IL-6], and tumor necrosis factor alpha [TNF-α]) and phosphor-nuclear factor kappa B (pNFκB) were significantly increased, while N-methyl-D-aspartate (NMDA) receptor subunits NR2A and NR2B, Ca2+/calmodulin-dependent protein kinase II (CaMKII), and brain-derived neurotrophic factor (BDNF) were down-regulated in the hippocampus and prefrontal cortex (PFC) of 22-months-old (aged) mice compared with 2-months-old (young adult) mice. Melatonin was administered in the drinking water to a cohort of the aged mice at a dose of 10 mg/kg/day, beginning at an age of 16 months for 6 months. Our results revealed that melatonin significantly attenuated the alterations in these protein levels. The present study suggests an advantageous role for melatonin in anti-inflammation, and this may lead to the prevention of memory impairment in aging.
Collapse
Affiliation(s)
| | - Patlada Tangweerasing
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Thailand
| | - Sujira Mukda
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Thailand
| | | | - Chutikorn Nopparat
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Thailand
| | - Piyarat Govitrapong
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Thailand.,Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Thailand.,Department of Pharmacology, Faculty of Science, Mahidol University, Thailand
| |
Collapse
|
15
|
Zhan JQ, Zheng LL, Chen HB, Yu B, Wang W, Wang T, Ruan B, Pan BX, Chen JR, Li XF, Wei B, Yang YJ. Hydrogen Sulfide Reverses Aging-Associated Amygdalar Synaptic Plasticity and Fear Memory Deficits in Rats. Front Neurosci 2018; 12:390. [PMID: 29930496 PMCID: PMC5999728 DOI: 10.3389/fnins.2018.00390] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/22/2018] [Indexed: 01/05/2023] Open
Abstract
As an endogenous neuromodulator, hydrogen sulfide (H2S) exerts multiple biological effects in the brain. Previous studies have shown that H2S is involved in the regulation of neural synaptic plasticity and cognition in healthy rodents. It is well known that there is a progressive decline of cognitive function that occurs with increased age. The purpose of this study was to investigate the role of H2S in aging-associated amygdalar synaptic plasticity and cued fear memory deficits as well as to explore the underlying mechanisms. We found that H2S levels in the amygdala were significantly lower in aged rats when compared with healthy adult rates, which displayed significant deficits in long-term potentiation (LTP) in the thalamo-lateral amygdala (LA) pathway and amygdala-dependent cued fear memory. Bath application of an H2S donor, sodium hydrogen sulfide (NaHS), significantly reversed the impaired LTP in brain slices from aged rats, and intra-LA infusion of NaHS restored the cued fear memory in aged rats. Mechanismly, we found that H2S treatment significantly enhanced NMDAR-mediated synaptic responses in the thalamo-LA pathway of aged rats. Notably, GluN2B-containing NMDARs, but not GluN2A-containing NMDARs, contributed to the effects of H2S on aging-associated impairments of amygdalar LTP and fear memory, because applying GluN2B antagonist could abolish the beneficial effects of NaHS treatment on amygdalar LTP and cognitive performance in aged rats. Collectively, these results show that H2S can reverse aging-associated amygdalar synaptic plasticity and fear memory deficits by restoring the function of GluN2B-containing NMDARs, suggesting that supplement of H2S might be a therapeutic approach for aging-related cognitive disorders.
Collapse
Affiliation(s)
- Jin-Qiong Zhan
- Biological Psychiatry Laboratory, Department of Psychiatry, Jiangxi Mental Hospital/Affiliated Mental Hospital of Nanchang University, Nanchang, China
| | - Li-Li Zheng
- Department of Pharmacy, Jiangxi Maternal and Child Health Hospital, Nanchang, China
| | - Hai-Bo Chen
- Biological Psychiatry Laboratory, Department of Psychiatry, Jiangxi Mental Hospital/Affiliated Mental Hospital of Nanchang University, Nanchang, China
| | - Bin Yu
- Biological Psychiatry Laboratory, Department of Psychiatry, Jiangxi Mental Hospital/Affiliated Mental Hospital of Nanchang University, Nanchang, China
| | - Wei Wang
- Department of Neurology, Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Ting Wang
- Department of Pharmacology, College of Medical Science, China Three Gorges University, Yichang, China
| | - Bo Ruan
- Department of Pharmacology, College of Medical Science, China Three Gorges University, Yichang, China
| | - Bin-Xing Pan
- Laboratory of Fear and Anxiety Disorders, Institute of Life Science, Nanchang University, Nanchang, China
| | - Juan-Ru Chen
- Biological Psychiatry Laboratory, Department of Psychiatry, Jiangxi Mental Hospital/Affiliated Mental Hospital of Nanchang University, Nanchang, China
| | - Xue-Fen Li
- Department of Neurology, Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Bo Wei
- Biological Psychiatry Laboratory, Department of Psychiatry, Jiangxi Mental Hospital/Affiliated Mental Hospital of Nanchang University, Nanchang, China
| | - Yuan-Jian Yang
- Biological Psychiatry Laboratory, Department of Psychiatry, Jiangxi Mental Hospital/Affiliated Mental Hospital of Nanchang University, Nanchang, China
| |
Collapse
|
16
|
Portero-Tresserra M, Martí-Nicolovius M, Tarrés-Gatius M, Candalija A, Guillazo-Blanch G, Vale-Martínez A. Intra-hippocampal D-cycloserine rescues decreased social memory, spatial learning reversal, and synaptophysin levels in aged rats. Psychopharmacology (Berl) 2018; 235:1463-1477. [PMID: 29492616 DOI: 10.1007/s00213-018-4858-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 02/15/2018] [Indexed: 01/08/2023]
Abstract
RATIONALE Aging is characterized by a decrease in N-methyl-D-aspartate receptors (NMDARs) in the hippocampus, which might be one of the factors involved in the age-dependent cognitive decline. D-Cycloserine (DCS), a partial agonist of the NMDAR glycine recognition site, could improve memory deficits associated to neurodegenerative disorders and cognitive deficits observed in normal aging. OBJECTIVES AND METHODS The aim of the present study was to explore whether DCS would reverse age-dependent memory deficits and decreases in NMDA receptor subunits (GluN1, GluN2A, and GluN2B) and the presynaptic protein synaptophysin in Wistar rats. We investigated the effects of pre-training infusions of DCS (10 μg/hemisphere) in the ventral hippocampus on two hippocampal-dependent learning tasks, the social transmission of food preference (STFP), and the Morris water maze (MWM). RESULTS The results revealed that infusions of DCS administered before the acquisition sessions rescued deficits in the STFP retention and MWM reversal learning in old rats. DCS also significantly increased the hippocampal levels of synaptophysin in old rats, which correlated with STFP and MWM performance in all tests. Moreover, although the levels of the GluN1 subunit correlated with the MWM acquisition and reversal, DCS did not enhance the expression of such synaptic protein. CONCLUSIONS The present behavioral results support the role of DCS as a cognitive enhancer and suggest that enhancing the function of NMDARs and synaptic plasticity in the hippocampus may be related to improvement in social memory and spatial learning reversal in aged animals.
Collapse
Affiliation(s)
- Marta Portero-Tresserra
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Margarita Martí-Nicolovius
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - Mireia Tarrés-Gatius
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Ana Candalija
- Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Gemma Guillazo-Blanch
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Anna Vale-Martínez
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| |
Collapse
|
17
|
Avila J, Llorens-Martín M, Pallas-Bazarra N, Bolós M, Perea JR, Rodríguez-Matellán A, Hernández F. Cognitive Decline in Neuronal Aging and Alzheimer's Disease: Role of NMDA Receptors and Associated Proteins. Front Neurosci 2017; 11:626. [PMID: 29176942 PMCID: PMC5687061 DOI: 10.3389/fnins.2017.00626] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 10/26/2017] [Indexed: 01/01/2023] Open
Abstract
Molecular changes associated with neuronal aging lead to a decrease in cognitive capacity. Here we discuss these alterations at the level of brain regions, brain cells, and brain membrane and cytoskeletal proteins with an special focus in NMDA molecular changes through aging and its effect in cognitive decline and Alzheimer disease. Here, we propose that some neurodegenerative disorders, like Alzheimer's disease (AD), are characterized by an increase and acceleration of some of these changes.
Collapse
Affiliation(s)
- Jesús Avila
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - María Llorens-Martín
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Noemí Pallas-Bazarra
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Marta Bolós
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Juan R Perea
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Alberto Rodríguez-Matellán
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Félix Hernández
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| |
Collapse
|
18
|
Nakaya N, Sultana A, Tomarev SI. Impaired AMPA receptor trafficking by a double knockout of zebrafish olfactomedin1a/b. J Neurochem 2017; 143:635-644. [PMID: 28975619 DOI: 10.1111/jnc.14231] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/15/2017] [Accepted: 09/27/2017] [Indexed: 01/06/2023]
Abstract
The olfm1a and olfm1b genes in zebrafish encode conserved secreted glycoproteins. These genes are preferentially expressed in the brain and retina starting from 16 h post-fertilization until adulthood. Functions of the Olfm1 gene is still unclear. Here, we produced and analyzed a null zebrafish mutant of both olfm1a and olfm1b genes (olfm1 null). olfm1 null fish were born at a normal Mendelian ratio and showed normal body shape and fertility as well as no visible defects from larval stages to adult. Olfm1 proteins were preferentially localized in the synaptosomes of the adult brain. Olfm1 co-immunoprecipitated with GluR2 and soluble NSF attachment protein receptor complexes indicating participation of Olfm1 in both pre- and post-synaptic events. Phosphorylation of GluR2 was not changed while palmitoylation of GluR2 was decreased in the brain synaptosomal membrane fraction of olfm1 null compared with wt fish. The levels of GluR2, SNAP25, flotillin1, and VAMP2 were markedly reduced in the synaptic microdomain of olfm1 null brain compared with wt. The internalization of GluR2 in retinal cells and the localization of VAMP2 in brain synaptosome were modified by olfm1 null mutation. This indicates that Olfm1 may regulate receptor trafficking from the intracellular compartments to the synaptic membrane microdomain, partly through the alteration of post-translational GluR2 modifications such as palmitoylation. Olfm1 may be considered a novel regulator of the composition and function of the α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor complex.
Collapse
Affiliation(s)
- Naoki Nakaya
- Section of Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Afia Sultana
- Section of Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Stanislav I Tomarev
- Section of Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, NIH, Bethesda, Maryland, USA
| |
Collapse
|
19
|
Attenuated Activity across Multiple Cell Types and Reduced Monosynaptic Connectivity in the Aged Perirhinal Cortex. J Neurosci 2017; 37:8965-8974. [PMID: 28821661 DOI: 10.1523/jneurosci.0531-17.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/25/2017] [Accepted: 08/04/2017] [Indexed: 01/25/2023] Open
Abstract
The perirhinal cortex (PER), which is critical for associative memory and stimulus discrimination, has been described as a wall of inhibition between the neocortex and hippocampus. With advanced age, rats show deficits on PER-dependent behavioral tasks and fewer PER principal neurons are activated by stimuli, but the role of PER interneurons in these altered circuit properties in old age has not been characterized. In the present study, PER neurons were recorded while rats traversed a circular track bidirectionally in which the track was either empty or contained eight novel objects evenly spaced around the track. Putative interneurons were discriminated from principal cells based on the autocorrelogram, waveform parameters, and firing rate. While object modulation of interneuron firing was observed in both young and aged rats, PER interneurons recorded from old animals had lower firing rates compared with those from young animals. This difference could not be accounted for by differences in running speed, as the firing rates of PER interneurons did not show significant velocity modulation. Finally, in the aged rats, relative to young rats, there was a significant reduction in detected excitatory and inhibitory monosynaptic connections. Together these data suggest that with advanced age there may be reduced afferent drive from excitatory cells onto interneurons that may compromise the wall of inhibition between the hippocampus and cortex. This circuit dysfunction could erode the function of temporal lobe networks and ultimately contribute to cognitive aging.SIGNIFICANCE STATEMENT We report that lower firing rates observed in aged perirhinal cortical principal cells are associated with weaker interneuron activity and reduced monosynaptic coupling between excitatory and inhibitory cells. This is likely to affect feedforward inhibition from the perirhinal to the entorhinal cortex that gates the flow of information to the hippocampus. This is significant because cognitive dysfunction in normative and pathological aging has been linked to hyperexcitability in the aged CA3 subregion of the hippocampus in rats, monkeys, and humans. The reduced inhibition in the perirhinal cortex reported here could contribute to this circuit imbalance, and may be a key point to consider for therapeutic interventions aimed at restoring network function to optimize cognition.
Collapse
|
20
|
Fan X, Wheatley EG, Villeda SA. Mechanisms of Hippocampal Aging and the Potential for Rejuvenation. Annu Rev Neurosci 2017; 40:251-272. [PMID: 28441118 DOI: 10.1146/annurev-neuro-072116-031357] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The past two decades have seen remarkable progress in our understanding of the multifactorial drivers of hippocampal aging and cognitive decline. Recent findings have also raised the possibility of functional rejuvenation in the aged hippocampus. In this review, we aim to synthesize the mechanisms that drive hippocampal aging and evaluate critically the potential for rejuvenation. We discuss the functional changes in synaptic plasticity and regenerative potential of the aged hippocampus, followed by mechanisms of microglia aging, and assess the cross talk between these proaging processes. We then examine proyouth interventions that demonstrate significant promise in reversing age-related impairments in the hippocampus and, finally, attempt to look ahead toward novel therapeutics for brain aging.
Collapse
Affiliation(s)
- Xuelai Fan
- Department of Anatomy, University of California, San Francisco, California 94143; , , .,The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, California 94143
| | - Elizabeth G Wheatley
- Department of Anatomy, University of California, San Francisco, California 94143; , , .,The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, California 94143.,Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, California 94143
| | - Saul A Villeda
- Department of Anatomy, University of California, San Francisco, California 94143; , , .,The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, California 94143.,Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, California 94143
| |
Collapse
|
21
|
NR2A-Containing NMDARs in the Prefrontal Cortex Are Required for Working Memory and Associated with Age-Related Cognitive Decline. J Neurosci 2016; 36:12537-12548. [PMID: 27807032 DOI: 10.1523/jneurosci.2332-16.2016] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/24/2016] [Accepted: 10/24/2016] [Indexed: 02/07/2023] Open
Abstract
Working memory, the ability to temporarily maintain representational knowledge, is a foundational cognitive process that can become compromised in aging and neuropsychiatric disease. NMDA receptor (NMDAR) activation in prefrontal cortex (PFC) is necessary for the pyramidal neuron activity believed to enable working memory; however, the distinct biophysical properties and localization of NMDARs containing NR2A and NR2B subunits suggest unique roles for NMDAR subtypes in PFC neural activity and working memory. Experiments herein show that working memory depends on NR2A- but not NR2B-NMDARs in PFC of rats and that NR2A-NMDARs mediate the majority of evoked NMDAR currents on layer 2/3 PFC pyramidal neurons. Moreover, attenuated expression of the NR2A but not the NR2B subunit in PFC associates with naturally occurring working memory impairment in aged rats. Finally, NMDAR currents and working memory are enhanced in aged rats by promoting activation of the NR2A-enriched synaptic pool of PFC NMDARs. These results implicate NR2A-NMDARs in normal working memory and suggest novel treatment strategies for improving working memory in cognitive disorders. SIGNIFICANCE STATEMENT Working memory, the ability to hold information "in mind," requires persistent activity of pyramidal neurons in prefrontal cortex (PFC) mediated by NMDA receptor (NMDAR) activation. NMDAR loss in PFC may account for working memory impairments in aging and psychiatric disease. Our studies demonstrate that NMDARs containing the NR2A subunit, but not the NR2B subunit, are required for working memory and that loss of NR2A predicts severity of age-related working memory impairment. The importance of NR2A to working memory is likely due its abundant contribution to pyramidal neuron activity and location at synaptic sites in PFC. This information is useful in designing new therapies to treat working memory impairments by enhancing the function of NR2A-containing NMDARs.
Collapse
|
22
|
Danka Mohammed CP, Rhee H, Phee B, Kim K, Kim H, Lee H, Park JH, Jung JH, Kim JY, Kim H, Park SK, Nam HG, Kim K. miR-204 downregulates EphB2 in aging mouse hippocampal neurons. Aging Cell 2016; 15:380-8. [PMID: 26799631 PMCID: PMC4783348 DOI: 10.1111/acel.12444] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2015] [Indexed: 11/28/2022] Open
Abstract
Hippocampal synaptic function and plasticity deteriorate with age, often resulting in learning and memory deficits. As MicroRNAs (miRNAs) are important regulators of neuronal protein expression, we examined whether miRNAs may contribute to this age‐associated decline in hippocampal function. We first compared the small RNA transcriptome of hippocampal tissues from young and old mice. Among 269 hippocampal miRNAs, 80 were differentially expressed (≥ twofold) among the age groups. We focused on 36 miRNAs upregulated in the old mice compared with those in the young mice. The potential targets of these 36 miRNAs included 11 critical Eph/Ephrin synaptic signaling components. The expression levels of several genes in the Eph/Ephrin pathway, including EphB2, were significantly downregulated in the aged hippocampus. EphB2 is a known regulator of synaptic plasticity in hippocampal neurons, in part by regulating the surface expression of the NMDA receptor NR1 subunit. We found that EphB2 is a direct target of miR‐204 among miRNAs that were upregulated with age. The transfection of primary hippocampal neurons with a miR‐204 mimic suppressed both EphB2 mRNA and protein expression and reduced the surface expression of NR1. Transfection of miR‐204 also decreased the total expression of NR1. miR‐204 induces senescence‐like phenotype in fully matured neurons as evidenced by an increase in p16‐positive cells. We suggest that aging is accompanied by the upregulation of miR‐204 in the hippocampus, which downregulates EphB2 and results in reduced surface and total NR1 expression. This mechanism may contribute to age‐associated decline in hippocampal synaptic plasticity and the related cognitive functions.
Collapse
Affiliation(s)
- Chand Parvez Danka Mohammed
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
- Department of New Biology DGIST Daegu 711‐873 Korea
- Department of Life Sciences POSTECH Pohang 790‐784 Korea
| | | | - Bong‐Kwan Phee
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
| | - Kunhyung Kim
- Department of New Biology DGIST Daegu 711‐873 Korea
| | - Hee‐Jin Kim
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
| | - Hyehyeon Lee
- Department of New Biology DGIST Daegu 711‐873 Korea
| | | | | | - Jeong Yeon Kim
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
| | - Hyoung‐Chin Kim
- Korea Research Institute of Bioscience and Biotechnology Ochang 363‐883 Korea
| | - Sang Ki Park
- Department of Life Sciences POSTECH Pohang 790‐784 Korea
| | - Hong Gil Nam
- Center for Plant Aging Research Institute for Basic Science (IBS) Daegu 711‐873 Korea
- Department of New Biology DGIST Daegu 711‐873 Korea
| | - Keetae Kim
- Department of New Biology DGIST Daegu 711‐873 Korea
| |
Collapse
|
23
|
Kumar A. NMDA Receptor Function During Senescence: Implication on Cognitive Performance. Front Neurosci 2015; 9:473. [PMID: 26732087 PMCID: PMC4679982 DOI: 10.3389/fnins.2015.00473] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 11/25/2015] [Indexed: 12/13/2022] Open
Abstract
N-methyl-D-aspartate (NMDA) receptors, a family of L-glutamate receptors, play an important role in learning and memory, and are critical for spatial memory. These receptors are tetrameric ion channels composed of a family of related subunits. One of the hallmarks of the aging human population is a decline in cognitive function; studies in the past couple of years have demonstrated deterioration in NMDA receptor subunit expression and function with advancing age. However, a direct relationship between impaired memory function and a decline in NMDA receptors is still ambiguous. Recent studies indicate a link between an age-associated NMDA receptor hypofunction and memory impairment and provide evidence that age-associated enhanced oxidative stress might be contributing to the alterations associated with senescence. However, clear evidence is still deficient in demonstrating the underlying mechanisms and a relationship between age-associated impaired cognitive faculties and NMDA receptor hypofunction. The current review intends to present an overview of the research findings regarding changes in expression of various NMDA receptor subunits and deficits in NMDA receptor function during senescence and its implication in age-associated impaired hippocampal-dependent memory function.
Collapse
Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, Evelyn F. and William L. McKnight Brain Institute, University of Florida Gainesville, FL, USA
| |
Collapse
|
24
|
Neurocognitive Aging and the Hippocampus across Species. Trends Neurosci 2015; 38:800-812. [PMID: 26607684 DOI: 10.1016/j.tins.2015.10.003] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/27/2015] [Accepted: 10/18/2015] [Indexed: 11/23/2022]
Abstract
There is extensive evidence that aging is associated with impairments in episodic memory. Many of these changes have been ascribed to neurobiological alterations to the hippocampal network and its input pathways. A cross-species consensus is beginning to emerge suggesting that subtle synaptic and functional changes within this network may underlie the majority of age-related memory impairments. In this review we survey convergent data from animal and human studies that have contributed significantly to our understanding of the brain-behavior relationships in this network, particularly in the aging brain. We utilize a cognitive as well as a neurobiological perspective and synthesize data across approaches and species to reach a more detailed understanding of age-related alterations in hippocampal memory function.
Collapse
|
25
|
Guidi M, Kumar A, Foster TC. Impaired attention and synaptic senescence of the prefrontal cortex involves redox regulation of NMDA receptors. J Neurosci 2015; 35:3966-77. [PMID: 25740525 PMCID: PMC4348191 DOI: 10.1523/jneurosci.3523-14.2015] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 12/23/2014] [Accepted: 01/21/2015] [Indexed: 01/05/2023] Open
Abstract
Young (3-6 months) and middle-age (10-14 months) rats were trained on the five-choice serial reaction time task. Attention and executive function deficits were apparent in middle-age animals observed as a decrease in choice accuracy, increase in omissions, and increased response latency. The behavioral differences were not due to alterations in sensorimotor function or a diminished motivational state. Electrophysiological characterization of synaptic transmission in slices from the mPFC indicated an age-related decrease in glutamatergic transmission. In particular, a robust decrease in N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic responses in the mPFC was correlated with several measures of attention. The decrease in NMDAR function was due in part to an altered redox state as bath application of the reducing agent, dithiothreitol, increased the NMDAR component of the synaptic response to a greater extent in middle-age animals. Together with previous work indicating that redox state mediates senescent physiology in the hippocampus, the results indicate that redox changes contribute to senescent synaptic function in vulnerable brain regions involved in age-related cognitive decline.
Collapse
Affiliation(s)
- Michael Guidi
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| | - Thomas C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| |
Collapse
|
26
|
Abstract
The perirhinal cortex (PRC) is proposed to both represent high-order sensory information and maintain those representations across delays. These cognitive processes are required for recognition memory, which declines during normal aging. Whether or not advanced age affects the ability of PRC principal cells to support these dual roles, however, is not known. The current experiment recorded PRC neurons as young and aged rats traversed a track. When objects were placed on the track, a subset of the neurons became active at discrete locations adjacent to objects. Importantly, the aged rats had a lower proportion of neurons that were activated by objects. Once PRC activity patterns in the presence of objects were established, however, both age groups maintained these representations across delays up to 2 h. These data support the hypothesis that age-associated deficits in stimulus recognition arise from impairments in high-order stimulus representation rather than difficulty in sustaining stable activity patterns over time.
Collapse
|
27
|
Lourenço CF, Ferreira NR, Santos RM, Lukacova N, Barbosa RM, Laranjinha J. The pattern of glutamate-induced nitric oxide dynamics in vivo and its correlation with nNOS expression in rat hippocampus, cerebral cortex and striatum. Brain Res 2014; 1554:1-11. [PMID: 24495843 DOI: 10.1016/j.brainres.2014.01.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 01/13/2014] [Accepted: 01/18/2014] [Indexed: 01/20/2023]
Abstract
Nitric oxide (NO) is a diffusible intercellular messenger, acting via volume signaling in the brain and, therefore, the knowledge of its temporal dynamics is determinant to the understanding of its neurobiological role. However, such an analysis in vivo is challenging and indirect or static approaches are mostly used to infer NO bioactivity. In the present work we measured the glutamate-dependent NO temporal dynamics in vivo in the hippocampus (CA1, CA3 and DG subregions), cerebral cortex and striatum, using NO selective microelectrodes. Concurrently, the immunolocalization of nNOS was evaluated in each region. A transitory increase in NO levels occurred at higher amplitudes in the striatum and hippocampus relatively to the cortex. In the hippocampus, subtle differences in the profiles of NO signals were observed along the trisynaptic loop, with CA1 exhibiting the largest signals. The topography of NO temporal dynamics did not fully overlap with the pattern of the density of nNOS expression, suggesting that, complementary to the distribution of nNOS, the local regulation of NO synthesis as well as the decay pathways critically determine the effective NO concentration sensed by a target within the diffusional spread of this free radical. In sum, the rate and pattern of NO changes here shown, by incorporating regulatory mechanisms and processes that affect NO synthesis and decay, provide refined information critical for the understanding of NO multiple actions in the brain.
Collapse
Affiliation(s)
- C F Lourenço
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - N R Ferreira
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - R M Santos
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - N Lukacova
- Institute of Neurobiology, Slovak Academy of Sciences, Soltésovej 4, 040 01 Kosice, Slovak Republic
| | - R M Barbosa
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - J Laranjinha
- Faculty of Pharmacy and Center for Neurosciences and Cell Biology, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
| |
Collapse
|
28
|
Molina DP, Ariwodola OJ, Weiner JL, Brunso-Bechtold JK, Adams MM. Growth hormone and insulin-like growth factor-I alter hippocampal excitatory synaptic transmission in young and old rats. AGE (DORDRECHT, NETHERLANDS) 2013; 35:1575-87. [PMID: 22851280 PMCID: PMC3776110 DOI: 10.1007/s11357-012-9460-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/11/2012] [Indexed: 06/01/2023]
Abstract
In rats, as in humans, normal aging is characterized by a decline in hippocampal-dependent learning and memory, as well as in glutamatergic function. Both growth hormone (GH) and insulin-like growth factor-I (IGF-I) levels have been reported to decrease with age, and treatment with either GH or IGF-I can ameliorate age-related cognitive decline. Interestingly, acute GH and IGF-I treatments enhance glutamatergic synaptic transmission in the rat hippocampus of juvenile animals. However, whether this enhancement also occurs in old rats, when cognitive impairment is ameliorated by GH and IGF-I (des-IGF-I), remains to be determined. To address this issue, we used an in vitro CA1 hippocampal slice preparation and extracellular recording techniques to study the effects of acute application of GH and IGF-I on compound field excitatory postsynaptic potentials (fEPSPs), as well as AMPA- and NMDA-dependent fEPSPs, in young adult (10 months) and old (28 months) rats. The results indicated that both GH and IGF-I increased compound-, AMPA-, and NMDA-dependent fEPSPs to a similar extent in slices from both age groups and that this augmentation was likely mediated via a postsynaptic mechanism. Initial characterization of the signaling cascades underlying these effects revealed that the GH-induced enhancement was not mediated by the JAK2 signaling element in either young adult or old rats but that the IGF-I-induced enhancement involved a PI3K-mediated mechanism in old, but not young adults. The present findings are consistent with a role for a GH- or IGF-I-induced enhancement of glutamatergic transmission in mitigating age-related cognitive impairment in old rats.
Collapse
Affiliation(s)
- Doris P. Molina
- />Departments of Neurobiology and Anatomy, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1010 USA
| | - Olusegun J. Ariwodola
- />Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1010 USA
| | - Jeff L. Weiner
- />Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1010 USA
| | - Judy K. Brunso-Bechtold
- />Departments of Neurobiology and Anatomy, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1010 USA
- />Roena Kulynych Center for Memory and Cognition Research, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1010 USA
| | - Michelle M. Adams
- />Departments of Neurobiology and Anatomy, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1010 USA
- />Roena Kulynych Center for Memory and Cognition Research, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1010 USA
- />Department of Psychology, Bilkent University, 06800 Bilkent, Ankara, Turkey
| |
Collapse
|
29
|
A comparison of random forest regression and multiple linear regression for prediction in neuroscience. J Neurosci Methods 2013; 220:85-91. [DOI: 10.1016/j.jneumeth.2013.08.024] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 08/13/2013] [Accepted: 08/28/2013] [Indexed: 11/20/2022]
|
30
|
Sonntag WE, Deak F, Ashpole N, Toth P, Csiszar A, Freeman W, Ungvari Z. Insulin-like growth factor-1 in CNS and cerebrovascular aging. Front Aging Neurosci 2013; 5:27. [PMID: 23847531 PMCID: PMC3698444 DOI: 10.3389/fnagi.2013.00027] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/14/2013] [Indexed: 12/26/2022] Open
Abstract
Insulin-like growth factor-1 (IGF-1) is an important anabolic hormone that decreases with age. In the past two decades, extensive research has determined that the reduction in IGF-1 is an important component of the age-related decline in cognitive function in multiple species including humans. Deficiency in circulating IGF-1 results in impairment in processing speed and deficiencies in both spatial and working memory. Replacement of IGF-1 or factors that increase IGF-1 to old animals and humans reverses many of these cognitive deficits. Despite the overwhelming evidence for IGF-1 as an important neurotrophic agent, the specific mechanisms through which IGF-1 acts have remained elusive. Recent evidence indicates that IGF-1 is both produced by and has important actions on the cerebrovasculature as well as neurons and glia. Nevertheless, the specific regulation and actions of brain- and vascular-derived IGF-1 is poorly understood. The diverse effects of IGF-1 discovered thus far reveal a complex endocrine and paracrine system essential for integrating many of the functions necessary for brain health. Identification of the mechanisms of IGF-1 actions will undoubtedly provide critical insight into regulation of brain function in general and the causes of cognitive decline with age.
Collapse
Affiliation(s)
- William E Sonntag
- Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center Oklahoma City, OK, USA
| | | | | | | | | | | | | |
Collapse
|
31
|
Huang YJ, Lin CH, Lane HY, Tsai GE. NMDA Neurotransmission Dysfunction in Behavioral and Psychological Symptoms of Alzheimer's Disease. Curr Neuropharmacol 2013; 10:272-85. [PMID: 23450042 PMCID: PMC3468881 DOI: 10.2174/157015912803217288] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/04/2012] [Accepted: 07/09/2012] [Indexed: 01/06/2023] Open
Abstract
Dementia has become an all-important disease because the population is aging rapidly and the cost of health care associated with dementia is ever increasing. In addition to cognitive function impairment, associated behavioral and psychological symptoms of dementia (BPSD) worsen patient’s quality of life and increase caregiver’s burden. Alzheimer’s disease is the most common type of dementia and both behavioral disturbance and cognitive impairment of Alzheimer’s disease are thought to be associated with the N-methyl-D-aspartate (NMDA) dysfunction as increasing evidence of dysfunctional glutamatergic neurotransmission had been reported in behavioral changes and cognitive decline in Alzheimer’s disease. We review the literature regarding dementia (especially Alzheimer’s disease), BPSD and relevant findings on glutamatergic and NMDA neurotransmission, including the effects of memantine, a NMDA receptor antagonist, and NMDA-enhancing agents, such as D-serine and D-cycloserine. Literatures suggest that behavioral disturbance and cognitive impairment of Alzheimer’s disease may be associated with excitatory neurotoxic effects which result in impairment of neuronal plasticity and degenerative processes. Memantine shows benefits in improving cognition, function, agitation/aggression and delusion in Alzheimer’s disease. On the other hand, some NMDA modulators which enhance NMDA function through the co-agonist binding site can also improve cognitive function and psychotic symptoms. We propose that modulating NMDA neurotransmission is effective in treating behavioral and psychological symptoms of Alzheimer’s disease. Prospective study using NMDA enhancers in patients with Alzheimer’s disease and associated behavioral disturbance is needed to verify this hypothesis.
Collapse
Affiliation(s)
- Yu-Jhen Huang
- Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan ; Department of Psychiatry, China Medical University Hospital, Taichung, Taiwan
| | | | | | | |
Collapse
|
32
|
Deak F, Sonntag WE. Aging, synaptic dysfunction, and insulin-like growth factor (IGF)-1. J Gerontol A Biol Sci Med Sci 2012; 67:611-25. [PMID: 22503992 PMCID: PMC3348499 DOI: 10.1093/gerona/gls118] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 03/16/2012] [Indexed: 01/05/2023] Open
Abstract
Insulin-like growth factor (IGF)-1 is an important neurotrophic hormone. Deficiency of this hormone has been reported to influence the genesis of cognitive impairment and dementia in the elderly patients. Nevertheless, there are studies indicating that cognitive function can be maintained into old age even in the absence of circulating IGF-1 and studies that link IGF-1 to an acceleration of neurological diseases. Although IGF-1 has a complex role in brain function, synaptic effects appear to be central to the IGF-1-induced improvement in learning and memory. In this review, synaptic mechanisms of learning and memory and the effects of IGF-1 on synaptic communication are discussed. The emerging data indicate that synaptic function decreases with age and that IGF-1 contributes to information processing in the brain. Further studies that detail the specific actions of this important neurotrophic hormone will likely lead to therapies that result in improved cognitive function for the elderly patients.
Collapse
Affiliation(s)
- Ferenc Deak
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida
| | - William E. Sonntag
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, Oklahoma City, Oklahoma
| |
Collapse
|
33
|
Kawamoto EM, Vivar C, Camandola S. Physiology and pathology of calcium signaling in the brain. Front Pharmacol 2012; 3:61. [PMID: 22518105 PMCID: PMC3325487 DOI: 10.3389/fphar.2012.00061] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 03/26/2012] [Indexed: 12/31/2022] Open
Abstract
Calcium (Ca(2+)) plays fundamental and diversified roles in neuronal plasticity. As second messenger of many signaling pathways, Ca(2+) as been shown to regulate neuronal gene expression, energy production, membrane excitability, synaptogenesis, synaptic transmission, and other processes underlying learning and memory and cell survival. The flexibility of Ca(2+) signaling is achieved by modifying cytosolic Ca(2+) concentrations via regulated opening of plasma membrane and subcellular Ca(2+) sensitive channels. The spatiotemporal patterns of intracellular Ca(2+) signals, and the ultimate cellular biological outcome, are also dependent upon termination mechanism, such as Ca(2+) buffering, extracellular extrusion, and intra-organelle sequestration. Because of the central role played by Ca(2+) in neuronal physiology, it is not surprising that even modest impairments of Ca(2+) homeostasis result in profound functional alterations. Despite their heterogeneous etiology neurodegenerative disorders, as well as the healthy aging process, are all characterized by disruption of Ca(2+) homeostasis and signaling. In this review we provide an overview of the main types of neuronal Ca(2+) channels and their role in neuronal plasticity. We will also discuss the participation of Ca(2+) signaling in neuronal aging and degeneration.
Collapse
Affiliation(s)
- Elisa Mitiko Kawamoto
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research ProgramBaltimore, MD, USA
| | - Carmen Vivar
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research ProgramBaltimore, MD, USA
| | - Simonetta Camandola
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research ProgramBaltimore, MD, USA
| |
Collapse
|
34
|
VanGuilder HD, Bixler GV, Sonntag WE, Freeman WM. Hippocampal expression of myelin-associated inhibitors is induced with age-related cognitive decline and correlates with deficits of spatial learning and memory. J Neurochem 2012; 121:77-98. [PMID: 22269040 PMCID: PMC3341628 DOI: 10.1111/j.1471-4159.2012.07671.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Impairment of cognitive functions including hippocampus-dependent spatial learning and memory affects nearly half of the aged population. Age-related cognitive decline is associated with synaptic dysfunction that occurs in the absence of neuronal cell loss, suggesting that impaired neuronal signaling and plasticity may underlie age-related deficits of cognitive function. Expression of myelin-associated inhibitors (MAIs) of synaptic plasticity, including the ligands myelin-associated glycoprotein, neurite outgrowth inhibitor A, and oligodendrocyte myelin glycoprotein, and their common receptor, Nogo-66 receptor, was examined in hippocampal synaptosomes and Cornu ammonis area (CA)1, CA3 and dentate gyrus subregions derived from adult (12-13 months) and aged (26-28 months) Fischer 344 × Brown Norway rats. Rats were behaviorally phenotyped by Morris water maze testing and classified as aged cognitively intact (n = 7-8) or aged cognitively impaired (n = 7-10) relative to adults (n = 5-7). MAI protein expression was induced in cognitively impaired, but not cognitively intact, aged rats and correlated with cognitive performance in individual rats. Immunohistochemical experiments demonstrated that up-regulation of MAIs occurs, in part, in hippocampal neuronal axons and somata. While a number of pathways and processes are altered with brain aging, we report a coordinated induction of myelin-associated inhibitors of functional and structural plasticity only in cognitively impaired aged rats. Induction of MAIs may decrease stimulus-induced synaptic strengthening and structural remodeling, ultimately impairing synaptic mechanisms of spatial learning and memory and resulting in cognitive decline.
Collapse
Affiliation(s)
- Heather D. VanGuilder
- Department of Pharmacology, R130, Hershey Center for Applied Research, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033 USA
| | - Georgina V. Bixler
- Department of Pharmacology, R130, Hershey Center for Applied Research, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033 USA
| | - William E. Sonntag
- Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Science Center, 975 NE 10th Street, BRC-1303, Oklahoma City OK 73104 USA
| | - Willard M. Freeman
- Department of Pharmacology, R130, Hershey Center for Applied Research, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033 USA
| |
Collapse
|
35
|
Garrido P, De Blas M, Giné E, Santos Á, Mora F. Aging impairs the control of prefrontal cortex on the release of corticosterone in response to stress and on memory consolidation. Neurobiol Aging 2012; 33:827.e1-9. [DOI: 10.1016/j.neurobiolaging.2011.06.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 02/28/2011] [Accepted: 06/17/2011] [Indexed: 12/27/2022]
|
36
|
Tse YC, Bagot RC, Wong TP. Dynamic regulation of NMDAR function in the adult brain by the stress hormone corticosterone. Front Cell Neurosci 2012; 6:9. [PMID: 22408607 PMCID: PMC3294281 DOI: 10.3389/fncel.2012.00009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 02/17/2012] [Indexed: 12/18/2022] Open
Abstract
Stress and corticosteroids dynamically modulate the expression of synaptic plasticity at glutamatergic synapses in the developed brain. Together with alpha-amino-3-hydroxy-methyl-4-isoxazole propionic acid receptors (AMPAR), N-methyl-D-aspartate receptors (NMDAR) are critical mediators of synaptic function and are essential for the induction of many forms of synaptic plasticity. Regulation of NMDAR function by cortisol/corticosterone (CORT) may be fundamental to the effects of stress on synaptic plasticity. Recent reports of the efficacy of NMDAR antagonists in treating certain stress-associated psychopathologies further highlight the importance of understanding the regulation of NMDAR function by CORT. Knowledge of how corticosteroids regulate NMDAR function within the adult brain is relatively sparse, perhaps due to a common belief that NMDAR function is stable in the adult brain. We review recent results from our laboratory and others demonstrating dynamic regulation of NMDAR function by CORT in the adult brain. In addition, we consider the issue of how differences in the early life environment may program differential sensitivity to modulation of NMDAR function by CORT and how this may influence synaptic function during stress. Findings from these studies demonstrate that NMDAR function in the adult hippocampus remains sensitive to even brief exposures to CORT and that the capacity for modulation of NMDAR may be programmed, in part, by the early life environment. Modulation of NMDAR function may contribute to dynamic regulation of synaptic plasticity and adaptation in the face of stress, however, enhanced NMDAR function may be implicated in mechanisms of stress-related psychopathologies including depression.
Collapse
Affiliation(s)
- Yiu Chung Tse
- Neuroscience Division, Douglas Mental Health University Institute, McGill University, Montreal QC, Canada
| | | | | |
Collapse
|
37
|
Abstract
Steroid hormones may alter mnemonic processes. The majority of investigations have focused on the effects of 17β-estradiol (E(2)) to mediate learning. However, progesterone (P(4)), which varies across endogenous hormonal milieu with E(2), may also have effects on cognitive processes. P(4) may have effects in the hippocampus, prefrontal cortex (PFC) and/or striatum to enhance cognitive performance. Cognitive performance/learning has been assessed using tasks that are mediated by the hippocampus (water maze), PFC (object recognition) and striatum (conditioning). Our findings suggest that progestogens can have pervasive effects to enhance cognitive performance and learning in tasks mediated by the hippocampus, PFC and striatum and that these effects may be in part independent of actions at intracellular progestin receptors. Progestogens may therefore influence cognitive processes.
Collapse
|
38
|
Vanguilder HD, Freeman WM. The hippocampal neuroproteome with aging and cognitive decline: past progress and future directions. Front Aging Neurosci 2011; 3:8. [PMID: 21647399 PMCID: PMC3102218 DOI: 10.3389/fnagi.2011.00008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 05/12/2011] [Indexed: 01/12/2023] Open
Abstract
Although steady progress on understanding brain aging has been made over recent decades through standard anatomical, immunohistochemical, and biochemical techniques, the biological basis of non-neurodegenerative cognitive decline with aging remains to be determined. This is due in part to technical limitations of traditional approaches, in which only a small fraction of neurobiologically relevant proteins, mRNAs or metabolites can be assessed at a time. With the development and refinement of proteomic technologies that enable simultaneous quantitative assessment of hundreds to thousands of proteins, neuroproteomic studies of brain aging and cognitive decline are becoming more widespread. This review focuses on the contributions of neuroproteomic investigations to advances in our understanding of age-related deficits of hippocampus-dependent spatial learning and memory. Accumulating neuroproteomic data demonstrate that hippocampal aging involves common themes of dysregulated metabolism, increased oxidative stress, altered protein processing, and decreased synaptic function. Additionally, growing evidence suggests that cognitive decline does not represent a "more aged" phenotype, but rather is associated with specific neuroproteomic changes that occur in addition to age-related alterations. Understanding if and how age-related changes in the hippocampal neuroproteome contribute to cognitive decline and elucidating the pathways and processes that lead to cognitive decline are critical objectives that remain to be achieved. Progress in the field and challenges that remain to be addressed with regard to animal models, behavioral testing, and proteomic reporting are also discussed.
Collapse
Affiliation(s)
- Heather D Vanguilder
- Department of Pharmacology, Penn State College of Medicine, Milton S. Hershey Medical Center Hershey, PA, USA
| | | |
Collapse
|
39
|
Yu DF, Wu PF, Fu H, Cheng J, Yang YJ, Chen T, Long LH, Chen JG, Wang F. Aging-related alterations in the expression and distribution of GluR2 and PICK1 in the rat hippocampus. Neurosci Lett 2011; 497:42-5. [PMID: 21527319 DOI: 10.1016/j.neulet.2011.04.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/20/2011] [Accepted: 04/08/2011] [Indexed: 01/23/2023]
Abstract
Deficit in synaptic plasticity in the hippocampus frequently occurs during normal aging. Although the protein level and calcium permeability of AMPARs alter with aging, the alteration of AMPARs and their regulatory proteins during aging are far from understanding. Dynamics of GluR2 subunit are dependent on the function of protein interacting with Cα kinase 1 (PICK1), PKCα and calcineurin (CaN). Here, we firstly show that the expression of PICK1 and CaN B decreased significantly in the hippocampus of old rats compared to that of young and adult rats. The decrease was accompanied by a reduction of GluR2 and PKCα and an increase in CaN A. Next, we found that in young and adult rats, the distribution of PICK1 and GluR2 diffused in the cytoplasm of hippocampal neurons, but closely around perinuclear in the hippocampal neurons of old rats. These results suggest that the expression of GluR2, PICK1, PKCα and CaN B significant decreased in the hippocampus and these alterations may lead to altered distribution of GluR2 and PICK1 during aging.
Collapse
Affiliation(s)
- Dan-Fang Yu
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
VanGuilder HD, Farley JA, Yan H, Van Kirk CA, Mitschelen M, Sonntag WE, Freeman WM. Hippocampal dysregulation of synaptic plasticity-associated proteins with age-related cognitive decline. Neurobiol Dis 2011; 43:201-12. [PMID: 21440628 DOI: 10.1016/j.nbd.2011.03.012] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 03/18/2011] [Indexed: 12/16/2022] Open
Abstract
Age-related cognitive decline occurs without frank neurodegeneration and is the most common cause of memory impairment in aging individuals. With increasing longevity, cognitive deficits, especially in hippocampus-dependent memory processes, are increasing in prevalence. Nevertheless, the neurobiological basis of age-related cognitive decline remains unknown. While concerted efforts have led to the identification of neurobiological changes with aging, few age-related alterations have been definitively correlated to behavioral measures of cognitive decline. In this work, adult (12 months) and aged (28 months) rats were categorized by Morris water maze performance as Adult cognitively Intact, Aged cognitively Intact or Aged cognitively Impaired, and protein expression was examined in hippocampal synaptosome preparations. Previously described differences in synaptic expression of neurotransmission-associated proteins (Dnm1, Hpca, Stx1, Syn1, Syn2, Syp, SNAP25, VAMP2 and 14-3-3 eta, gamma, and zeta) were confirmed between Adult and Aged rats, with no further dysregulation associated with cognitive impairment. Proteins related to synaptic structural stability (MAP2, drebrin, Nogo-A) and activity-dependent signaling (PSD-95, 14-3-3θ, CaMKIIα) were up- and down-regulated, respectively, with cognitive impairment but were not altered with increasing age. Localization of MAP2, PSD-95, and CaMKIIα demonstrated protein expression alterations throughout the hippocampus. The altered expression of activity- and structural stability-associated proteins suggests that impaired synaptic plasticity is a distinct phenomenon that occurs with age-related cognitive decline, and demonstrates that cognitive decline is not simply an exacerbation of the aging phenotype.
Collapse
Affiliation(s)
- Heather D VanGuilder
- Penn State College of Medicine, Department of Pharmacology, Hershey Center for Applied Research, 500 University Drive, Hershey, PA 17033, USA
| | | | | | | | | | | | | |
Collapse
|
41
|
Motevasseli T, Rezayof A, Zarrindast MR, Nayer-Nouri T. Role of ventral hippocampal NMDA receptors in anxiolytic-like effect of morphine. Physiol Behav 2010; 101:608-13. [DOI: 10.1016/j.physbeh.2010.09.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 07/30/2010] [Accepted: 09/20/2010] [Indexed: 11/26/2022]
|
42
|
Nicholson AM, Methner DNR, Ferreira A. Membrane cholesterol modulates {beta}-amyloid-dependent tau cleavage by inducing changes in the membrane content and localization of N-methyl-D-aspartic acid receptors. J Biol Chem 2010; 286:976-86. [PMID: 21047784 DOI: 10.1074/jbc.m110.154138] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that β-amyloid (Aβ) treatment resulted in an age-dependent calpain activation leading to Tau cleavage into a neurotoxic 17-kDa fragment in a cellular model of Alzheimer disease. This detrimental cellular response was mediated by a developmentally regulated increase in membrane cholesterol levels. In this study, we assessed the molecular mechanisms by which cholesterol modulated Aβ-induced Tau cleavage in cultured hippocampal neurons. Our results indicated that these mechanisms did not involve the regulation of the binding of Aβ aggregates to the plasma membrane. On the other hand, experiments using N-methyl-d-aspartic acid receptor inhibitors suggested that these receptors played an essential role in cholesterol-mediated Aβ-dependent calpain activity and 17-kDa Tau production. Biochemical and immunocytochemical analyses demonstrated that decreasing membrane cholesterol levels in mature neurons resulted in a significant reduction of the NR1 subunit at the membrane as well as an increase in the number of large NR1, NR2A, and NR2B subunit clusters. Moreover, the majority of these larger N-methyl-d-aspartic acid receptor subunit immunoreactive spots was not juxtaposed to presynaptic sites in cholesterol-reduced neurons. These data suggested that changes at the synaptic level underlie the mechanism by which membrane cholesterol modulates developmental changes in the susceptibility of hippocampal neurons to Aβ-induced toxicity.
Collapse
Affiliation(s)
- Alexandra M Nicholson
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | | | | |
Collapse
|
43
|
Differential response of AMPA and NMDA glutamate receptors of Purkinje cells to aging of the chicken cerebellum. Neurosci Lett 2010; 478:146-9. [DOI: 10.1016/j.neulet.2010.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Revised: 04/19/2010] [Accepted: 05/04/2010] [Indexed: 11/19/2022]
|
44
|
Montori S, Dos-Anjos S, Martínez-Villayandre B, Regueiro-Purriños MM, Gonzalo-Orden JM, Ruano D, Fernández-López A. Age and meloxicam attenuate the ischemia/reperfusion-induced down-regulation in the NMDA receptor genes. Neurochem Int 2010; 56:878-85. [DOI: 10.1016/j.neuint.2010.03.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 03/17/2010] [Accepted: 03/21/2010] [Indexed: 12/24/2022]
|
45
|
VanGuilder HD, Yan H, Farley JA, Sonntag WE, Freeman WM. Aging alters the expression of neurotransmission-regulating proteins in the hippocampal synaptoproteome. J Neurochem 2010; 113:1577-88. [PMID: 20374424 DOI: 10.1111/j.1471-4159.2010.06719.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Decreased cognitive performance reduces independence and quality of life for aging individuals. Healthy brain aging does not involve significant neuronal loss, but little is known about the effects of aging at synaptic terminals. Age-related cognitive decline likely reflects the manifestation of dysregulated synaptic function and ineffective neurotransmission. In this study, hippocampal synaptosomes were enriched from young-adult (3 months), adult (12 months), and aged (26 months) Fischer 344 x Brown Norway rats, and quantitative alterations in the synaptoproteome were examined by 2-DIGE and MS/MS. Bioinformatic analysis of differentially expressed proteins identified a significant effect of aging on a network of neurotransmission-regulating proteins. Specifically, altered expression of DNM1, HPCA, PSD95, SNAP25, STX1, SYN1, SYN2, SYP, and VAMP2 was confirmed by immunoblotting. 14-3-3 isoforms identified in the proteomic analysis were also confirmed as a result of their implication in the regulation of the synaptic vesicle cycle and neurotransmission modulation. The findings of this study demonstrate a coordinated down-regulation of neurotransmission-regulating proteins that suggests an age-based deterioration of hippocampal neurotransmission occurring between adulthood and advanced age. Altered synaptic protein expression may decrease stimulus-induced neurotransmission and vesicle replenishment during prolonged or intense stimulation, which are necessary for learning and the formation and perseverance of memory.
Collapse
Affiliation(s)
- Heather D VanGuilder
- Department of Pharmacology, Hershey Center for Applied Research, Penn State College of Medicine, University Drive, Hershey, Pennsylvania 17033, USA
| | | | | | | | | |
Collapse
|
46
|
Magnusson KR, Brim BL, Das SR. Selective Vulnerabilities of N-methyl-D-aspartate (NMDA) Receptors During Brain Aging. Front Aging Neurosci 2010; 2:11. [PMID: 20552049 PMCID: PMC2874396 DOI: 10.3389/fnagi.2010.00011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 03/02/2010] [Indexed: 01/07/2023] Open
Abstract
N-methyl-D-aspartate (NMDA) receptors are present in high density within the cerebral cortex and hippocampus and play an important role in learning and memory. NMDA receptors are negatively affected by aging, but these effects are not uniform in many different ways. This review discusses the selective age-related vulnerabilities of different binding sites of the NMDA receptor complex, different subunits that comprise the complex, and the expression and functions of the receptor within different brain regions. Spatial reference, passive avoidance, and working memory, as well as place field stability and expansion all involve NMDA receptors. Aged animals show deficiencies in these functions, as compared to young, and some studies have identified an association between age-associated changes in the expression of NMDA receptors and poor memory performance. A number of diet and drug interventions have shown potential for reversing or slowing the effects of aging on the NMDA receptor. On the other hand, there is mounting evidence that the NMDA receptors that remain within aged individuals are not always associated with good cognitive functioning. This may be due to a compensatory response of neurons to the decline in NMDA receptor expression or a change in the subunit composition of the remaining receptors. These studies suggest that developing treatments that are aimed at preventing or reversing the effects of aging on the NMDA receptor may aid in ameliorating the memory declines that are associated with aging. However, we need to be mindful of the possibility that there may also be negative consequences in aged individuals.
Collapse
Affiliation(s)
- Kathy R Magnusson
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR, USA
| | | | | |
Collapse
|
47
|
Kumar A, Bodhinathan K, Foster TC. Susceptibility to Calcium Dysregulation during Brain Aging. Front Aging Neurosci 2009; 1:2. [PMID: 20552053 PMCID: PMC2874411 DOI: 10.3389/neuro.24.002.2009] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/27/2009] [Indexed: 01/06/2023] Open
Abstract
Calcium (Ca(2+)) is a highly versatile intracellular signaling molecule that is essential for regulating a variety of cellular and physiological processes ranging from fertilization to programmed cell death. Research has provided ample evidence that brain aging is associated with altered Ca(2+) homeostasis. Much of the work has focused on the hippocampus, a brain region critically involved in learning and memory, which is particularly susceptible to dysfunction during senescence. The current review takes a broader perspective, assessing age-related changes in Ca(2+) sources, Ca(2+) sequestration, and Ca(2+) binding proteins throughout the nervous system. The nature of altered Ca(2+) homeostasis is cell specific and may represent a deficit or a compensatory mechanism, producing complex patterns of impaired cellular function. Incorporating the knowledge of the complexity of age-related alterations in Ca(2+) homeostasis will positively shape the development of highly effective therapeutics to treat brain disorders.
Collapse
Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida Gainesville, FL, USA
| | | | | |
Collapse
|
48
|
The unsolved relationship of brain aging and late-onset Alzheimer disease. Biochim Biophys Acta Gen Subj 2009; 1790:1124-32. [DOI: 10.1016/j.bbagen.2009.07.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Revised: 07/08/2009] [Accepted: 07/10/2009] [Indexed: 11/23/2022]
|
49
|
Age-related changes in polyamines in memory-associated brain structures in rats. Neuroscience 2008; 155:789-96. [PMID: 18621105 DOI: 10.1016/j.neuroscience.2008.06.033] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2008] [Revised: 06/17/2008] [Accepted: 06/17/2008] [Indexed: 11/24/2022]
Abstract
Polyamines putrescine, spermidine and spermine are positively charged aliphatic amines and have important roles in maintaining normal cellular function, regulating neurotransmitter receptors and modulating learning and memory. Recent evidence suggests a role of putrescine in hippocampal neurogenesis, that is significantly impaired during aging. The present study measured the polyamine levels in memory-related brain structures in 24- (aged), 12- (middle-aged) and 4- (young) month-old rats using liquid chromatography/mass spectrometry and high performance liquid chromatography. In the hippocampus, the putrescine levels were significantly decreased in the CA1 and dentate gyrus, and increased in the CA2/3 with age. Significant age-related increases in the spermidine levels were found in the CA1 and CA2/3. There was no difference between groups in spermine in any sub-regions examined. In the parahippocampal region, increased putrescine level with age was observed in the entorhinal cortex, and age did not alter the spermidine levels. The spermine level was significantly decreased in the perirhinal cortex and increased in the postrhinal cortex with age. In the prefrontal cortex, there was age-related decrease in putrescine, and the spermidine and spermine levels were significantly increased with age. This study, for the first time, demonstrates age-related region-specific changes in polyamines in memory-associated structures, suggesting that polyamine system dysfunction may potentially contribute to aged-related impairments in hippocampal neurogenesis and learning and memory.
Collapse
|