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Yegla B, Rani A, Kumar A. Viral vector-mediated upregulation of serine racemase expression in medial prefrontal cortex improves learning and synaptic function in middle age rats. Aging (Albany NY) 2023; 15:2433-2449. [PMID: 37052995 PMCID: PMC10120901 DOI: 10.18632/aging.204652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
An age-associated decrease in N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic function contributes to impaired synaptic plasticity and is associated with cognitive impairments. Levels of serine racemase (SR), an enzyme that synthesizes D-serine, an NMDAR co-agonist, decline with age. Thus, enhancing NMDAR function via increased SR expression in middle age, when subtle declines in cognition emerge, was predicted to enhance performance on a prefrontal cortex-mediated task sensitive to aging. Middle-aged (~12 mo) male Fischer-344 rats were injected bilaterally in the medial prefrontal cortex (mPFC) with viral vector (LV), SR (LV-SR) or control (LV-GFP). Rats were trained on the operant attentional set-shift task (AST) to examine cognitive flexibility and attentional function. LV-SR rats exhibited a faster rate of learning compared to controls during visual discrimination of the AST. Extradimensional set shifting and reversal were not impacted. Immunohistochemical analyses demonstrated that LV-SR significantly increased SR expression in the mPFC. Electrophysiological characterization of synaptic transmission in the mPFC slices obtained from LV-GFP and LV-SR animals indicated a significant increase in isolated NMDAR-mediated synaptic responses in LV-SR slices. Thus, results of the current study demonstrated that prefrontal SR upregulation in middle age rats can improve learning of task contingencies for visual discrimination and increase glutamatergic synaptic transmission, including NMDAR activity.
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Affiliation(s)
- Brittney Yegla
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Asha Rani
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
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Piubelli L, Murtas G, Rabattoni V, Pollegioni L. The Role of D-Amino Acids in Alzheimer's Disease. J Alzheimers Dis 2021; 80:475-492. [PMID: 33554911 DOI: 10.3233/jad-201217] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD), the main cause of dementia worldwide, is characterized by a complex and multifactorial etiology. In large part, excitatory neurotransmission in the central nervous system is mediated by glutamate and its receptors are involved in synaptic plasticity. The N-methyl-D-aspartate (NMDA) receptors, which require the agonist glutamate and a coagonist such as glycine or the D-enantiomer of serine for activation, play a main role here. A second D-amino acid, D-aspartate, acts as agonist of NMDA receptors. D-amino acids, present in low amounts in nature and long considered to be of bacterial origin, have distinctive functions in mammals. In recent years, alterations in physiological levels of various D-amino acids have been linked to various pathological states, ranging from chronic kidney disease to neurological disorders. Actually, the level of NMDA receptor signaling must be balanced to promote neuronal survival and prevent neurodegeneration: this signaling in AD is affected mainly by glutamate availability and modulation of the receptor's functions. Here, we report the experimental findings linking D-serine and D-aspartate, through NMDA receptor modulation, to AD and cognitive functions. Interestingly, AD progression has been also associated with the enzymes related to D-amino acid metabolism as well as with glucose and serine metabolism. Furthermore, the D-serine and D-/total serine ratio in serum have been recently proposed as biomarkers of AD progression. A greater understanding of the role of D-amino acids in excitotoxicity related to the pathogenesis of AD will facilitate novel therapeutic treatments to cure the disease and improve life expectancy.
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Affiliation(s)
- Luciano Piubelli
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Giulia Murtas
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Valentina Rabattoni
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Loredano Pollegioni
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
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Chang CH, Kuo HL, Ma WF, Tsai HC. Cerebrospinal Fluid and Serum d-Serine Levels in Patients with Alzheimer's Disease: A Systematic Review and Meta-Analysis. J Clin Med 2020; 9:E3840. [PMID: 33256147 PMCID: PMC7761499 DOI: 10.3390/jcm9123840] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE Alzheimer's disease (AD) is a complex and severe neurodegenerative disease and still lacks effective methods of diagnosis. Dysfunction of the N-methyl-D-aspartate receptor (NMDAR) has been found to be involved in synapse dysfunction and neurotoxicity of AD mechanisms. d-Serine, an NMDAR receptor coagonist, is reported as a potential new biomarker for AD. However, the results of serum and cerebrospinal fluid (CSF) d-serine levels are conflicting. We conducted a meta-analysis to investigate the serum and CSF d-serine levels in patients with AD. METHODS We searched PubMed, the Cochrane central register of controlled trials, and the Cochrane database of systematic reviews for trials that measured d-serine levels both in patients with AD and in controls. We included controlled trials that analyzed d-serine levels in human samples (e.g., serum and CSF). Studies were pooled using a random-effect model for comparisons between AD and control group. We used effect size (ES; expressed as d-serine levels) in each selected meta-analysis to calculate standardized mean difference (SMD). Positive values indicated increased d-serine levels in AD group. We presented results with 95% confidence intervals (CIs). The heterogeneity of the included trials was evaluated through visually inspecting funnel plots and using the I2 statistic. Moderators of effects were explored using metaregression. RESULTS Seven trials with more than 1186 participants were included in this meta-analysis. d-serine levels in patients with AD were significantly higher than those in controls (SMD = 0.679, 95% CI = 0.335 to 1.022, p < 0.001). Subgroup analyses showed that the AD group had significantly higher d-serine levels in serum and CSF compared with the control group (SMD = 0.566 (serum) and 1.008 (CSF); 95% CI = 0.183 to 0.948 (serum) and 0.168 to 1.849 (CSF)). Moreover, a metaregression revealed a significant negative association between ES and mean mini-mental state examination score in AD group (slope = -0.1203, p = 0.0004). CONCLUSIONS Our results revealed higher d-serine levels in the serum and CSF of patients with AD relative to the controls. Further studies with a larger sample size and longer follow-up are recommended to clarify this association.
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Affiliation(s)
- Chun-Hung Chang
- Institute of Clinical Medical Science, China Medical University, Taichung 40402, Taiwan;
- Department of Psychiatry & Brain Disease Research Center, China Medical University Hospital, Taichung 40402, Taiwan
- An Nan Hospital, China Medical University, Tainan 709204, Taiwan;
| | - Hsiao-Lun Kuo
- An Nan Hospital, China Medical University, Tainan 709204, Taiwan;
- School of Nursing, China Medical University, Taichung 40402, Taiwan;
| | - Wei-Fen Ma
- School of Nursing, China Medical University, Taichung 40402, Taiwan;
- Ph.D Program for Health Science and Industry, China Medical University, Taichung 40402, Taiwan
- Adjunct Supervisor, Department of Nursing, China Medical University Hospital, Taichung 40402, Taiwan
| | - Hsin-Chi Tsai
- Department of Psychiatry, Tzu-Chi General Hospital, Hualien 970473, Taiwan
- Institute of Medical Sciences, Tzu Chi University, Hualien 970473, Taiwan
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Shepherd A, May C, Churilov L, Adlard PA, Hannan AJ, Burrows EL. Evaluation of attention in APP/PS1 mice shows impulsive and compulsive behaviours. GENES BRAIN AND BEHAVIOR 2019; 20:e12594. [PMID: 31177612 DOI: 10.1111/gbb.12594] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/06/2019] [Accepted: 06/06/2019] [Indexed: 12/20/2022]
Abstract
While Alzheimer's disease (AD) is traditionally associated with deficits in episodic memory, early changes in other cognitive domains, such as attention, have been gaining interest. In line with clinical observations, some animal models of AD have been shown to develop attentional deficits, but this is not consistent across all models. The APPswe/PS1ΔE9 (APP/PS1) mouse is one of the most commonly used AD models and attention has not yet been scrutinised in this model. We set out to assess attention using the 5-choice serial reaction time task (5CSRTT) early in the progression of cognitive symptoms in APP/PS1 mice, using clinically translatable touchscreen chambers. APP/PS1 mice showed no attentional changes across 5CSRTT training or any probes from 9 to 11 months of age. Interestingly, APP/PS1 mice showed increased impulsive and compulsive responding when task difficulty was high. This suggests that while the APP/PS1 mouse model may not be a good model of attentional changes in AD, it may be useful to study the early changes in impulsive and compulsive behaviour that have been identified in patient studies. As these changes have not previously been reported without attentional deficits in the clinic, the APP/PS1 mouse model may provide a unique opportunity to study these specific behavioural changes seen in AD, including their mechanistic underpinnings and therapeutic implications.
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Affiliation(s)
- Amy Shepherd
- Florey Institute of Neuroscience and Mental Health, Kenneth Myer Building, University of Melbourne, Parkville, Victoria, Australia
| | - Carlos May
- Florey Institute of Neuroscience and Mental Health, Kenneth Myer Building, University of Melbourne, Parkville, Victoria, Australia
| | - Leonid Churilov
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Heidelberg, Victoria, Australia
| | - Paul A Adlard
- Florey Institute of Neuroscience and Mental Health, Kenneth Myer Building, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Kenneth Myer Building, University of Melbourne, Parkville, Victoria, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia
| | - Emma L Burrows
- Florey Institute of Neuroscience and Mental Health, Kenneth Myer Building, University of Melbourne, Parkville, Victoria, Australia
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The glycine site of NMDA receptors: A target for cognitive enhancement in psychiatric disorders. Prog Neuropsychopharmacol Biol Psychiatry 2019; 92:387-404. [PMID: 30738126 DOI: 10.1016/j.pnpbp.2019.02.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/29/2019] [Accepted: 02/01/2019] [Indexed: 01/05/2023]
Abstract
Cognitive dysfunction is a principal determinant of functional impairment in major depressive disorder (MDD) and often persists during periods of euthymia. Abnormalities in the glutamate system, particularly in N-methyl-d-aspartate receptors (NMDARs) activity, have been shown to contribute to both mood and cognitive symptoms in MDD. The current narrative review aims to evaluate the potential pro-cognitive effects of targeting the glycine site of NMDARs in the treatment of psychiatric disorders, with a special focus on how these results may apply to MDD. Literature databases were searched from inception to May 2018 for relevant pre-clinical and clinical studies evaluating antidepressant and pro-cognitive effects of NMDAR glycine site modulators in both MDD and non-MDD samples. Six glycine site modulators with pro-cognitive and antidepressant properties were identified: d-serine (co-agonist), d-cycloserine (partial agonist), d-alanine (co-agonist), glycine (agonist), sarcosine (co-agonist) and rapastinel (partial agonist). Preclinical animal studies demonstrated improved neuroplasticity and pro-cognitive effects with these agents. Numerous proof-of-concept clinical trials demonstrated pro-cognitive and antidepressant effects trans-diagnostically (e.g., in healthy participants, MDD, schizophrenia, anxiety disorders, major neurocognitive disorders). The generalizability of these clinical studies was limited by the small sample sizes and the paucity of studies directly evaluating cognitive effects in MDD samples, as most clinical trials were in non-MDD samples. Taken together, preliminary results suggest that the glycine site of NMDARs is a promising target to ameliorate symptoms of depression and cognitive dysfunction. Additional rigorously designed clinical studies are required to determine the cognitive effects of these agents in MDD.
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Cès A, Burg T, Herbeaux K, Héraud C, Bott JB, Mensah-Nyagan AG, Mathis C. Age-related vulnerability of pattern separation in C57BL/6J mice. Neurobiol Aging 2017; 62:120-129. [PMID: 29149630 DOI: 10.1016/j.neurobiolaging.2017.10.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 09/25/2017] [Accepted: 10/16/2017] [Indexed: 01/22/2023]
Abstract
Aging is associated with impaired performance in behavioral pattern separation (PS) tasks based on similarities in object features and in object location. These deficits have been attributed to functional alterations in the dentate gyrus (DG)-CA3 region. Animal studies suggested a role of adult-born DG neurons in PS performance. The present study investigated the effect of aging in C57BL/6J mice performing PS tasks based on either object features or object location. At the age of 18 months or more, performance was severely impaired in both tasks. Spatial PS performance declined gradually over adult lifespan from 3 to 21 months. Subchronic treatment with the cognitive enhancer D-serine fully rescued spatial PS performance in 18-month-old mice and induced a modest increase in the number of 4-week-old adult-born cells in the DG. Performance of mice in these PS tasks shows an age dependence, which appears to translate well to that found in humans. This model should help in deciphering physiological changes underlying PS deficits and in identifying future therapeutic targets.
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Affiliation(s)
- Aurélia Cès
- Université de Strasbourg, CNRS UMR 7364, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), 12 Rue Goethe, Strasbourg, France
| | - Thibaut Burg
- Université de Strasbourg, CNRS UMR 7364, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), 12 Rue Goethe, Strasbourg, France
| | - Karine Herbeaux
- Université de Strasbourg, CNRS UMR 7364, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), 12 Rue Goethe, Strasbourg, France
| | - Céline Héraud
- Université de Strasbourg, CNRS UMR 7364, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), 12 Rue Goethe, Strasbourg, France
| | - Jean-Bastien Bott
- Université de Strasbourg, CNRS UMR 7364, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), 12 Rue Goethe, Strasbourg, France
| | - Ayikoe Guy Mensah-Nyagan
- Université de Strasbourg, INSERM U1119, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Bâtiment 3 de la Faculté de Médecine, 11 Rue Humann, Strasbourg, France
| | - Chantal Mathis
- Université de Strasbourg, CNRS UMR 7364, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), 12 Rue Goethe, Strasbourg, France.
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Madeira C, Lourenco MV, Vargas-Lopes C, Suemoto CK, Brandão CO, Reis T, Leite REP, Laks J, Jacob-Filho W, Pasqualucci CA, Grinberg LT, Ferreira ST, Panizzutti R. d-serine levels in Alzheimer's disease: implications for novel biomarker development. Transl Psychiatry 2015; 5:e561. [PMID: 25942042 PMCID: PMC4471283 DOI: 10.1038/tp.2015.52] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 01/19/2015] [Accepted: 02/08/2015] [Indexed: 02/08/2023] Open
Abstract
Alzheimer's disease (AD) is a severe neurodegenerative disorder still in search of effective methods of diagnosis. Altered levels of the NMDA receptor co-agonist, d-serine, have been associated with neurological disorders, including schizophrenia and epilepsy. However, whether d-serine levels are deregulated in AD remains elusive. Here, we first measured D-serine levels in post-mortem hippocampal and cortical samples from nondemented subjects (n=8) and AD patients (n=14). We next determined d-serine levels in experimental models of AD, including wild-type rats and mice that received intracerebroventricular injections of amyloid-β oligomers, and APP/PS1 transgenic mice. Finally, we assessed d-serine levels in the cerebrospinal fluid (CSF) of 21 patients with a diagnosis of probable AD, as compared with patients with normal pressure hydrocephalus (n=9), major depression (n=9) and healthy controls (n=10), and results were contrasted with CSF amyloid-β/tau AD biomarkers. d-serine levels were higher in the hippocampus and parietal cortex of AD patients than in control subjects. Levels of both d-serine and serine racemase, the enzyme responsible for d-serine production, were elevated in experimental models of AD. Significantly, d-serine levels were higher in the CSF of probable AD patients than in non-cognitively impaired subject groups. Combining d-serine levels to the amyloid/tau index remarkably increased the sensitivity and specificity of diagnosis of probable AD in our cohort. Our results show that increased brain and CSF d-serine levels are associated with AD. CSF d-serine levels discriminated between nondemented and AD patients in our cohort and might constitute a novel candidate biomarker for early AD diagnosis.
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Affiliation(s)
- C Madeira
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - M V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - C Vargas-Lopes
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - C K Suemoto
- Discipline of Geriatrics, University of São Paulo Medical School, Sao Paulo, Brazil
| | - C O Brandão
- Institute of Psychiatry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - T Reis
- Institute of Psychiatry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - R E P Leite
- Department of Pathology, University of São Paulo Medical School, Sao Paulo, Brazil
| | - J Laks
- Institute of Psychiatry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - W Jacob-Filho
- Discipline of Geriatrics, University of São Paulo Medical School, Sao Paulo, Brazil
| | - C A Pasqualucci
- Department of Pathology, University of São Paulo Medical School, Sao Paulo, Brazil
| | - L T Grinberg
- Department of Pathology, University of São Paulo Medical School, Sao Paulo, Brazil
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, CA, USA
| | - S T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - R Panizzutti
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- Institute of Psychiatry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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Memory formation and retention are affected in adult miR-132/212 knockout mice. Behav Brain Res 2015; 287:15-26. [PMID: 25813747 DOI: 10.1016/j.bbr.2015.03.032] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/11/2015] [Accepted: 03/16/2015] [Indexed: 01/16/2023]
Abstract
The miR-132/212 family is thought to play an important role in neural function and plasticity, while its misregulation has been observed in various neurodegenerative disorders. In this study, we analyzed 6-month-old miR-132/212 knockout mice in a battery of cognitive and non-cognitive behavioral tests. No significant changes were observed in reflexes and basic sensorimotor functions as determined by the SHIRPA primary screen. Accordingly, miR-132/212 knockout mice did not differ from wild-type controls in general locomotor activity in an open-field test. Furthermore, no significant changes of anxiety were measured in an elevated plus maze task. However, the mutant mice showed retention phase defects in a novel object recognition test and in the T-water maze. Moreover, the learning and probe phases in the Barnes maze were clearly altered in knockout mice when compared to controls. Finally, changes in BDNF, CREB, and MeCP2 were identified in the miR-132/212-deficient mice, providing a potential mechanism for promoting memory loss. Taken together, these results further strengthen the role of miR-132/212 in memory formation and retention, and shed light on the potential consequences of its deregulation in neurodegenerative diseases.
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Sultan S, Gebara EG, Moullec K, Toni N. D-serine increases adult hippocampal neurogenesis. Front Neurosci 2013; 7:155. [PMID: 24009551 PMCID: PMC3756301 DOI: 10.3389/fnins.2013.00155] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 08/12/2013] [Indexed: 12/16/2022] Open
Abstract
Adult hippocampal neurogenesis results in the continuous formation of new neurons and is a process of brain plasticity involved in learning and memory. The neurogenic niche regulates the stem cell proliferation and the differentiation and survival of new neurons and a major contributor to the neurogenic niche are astrocytes. Among the molecules secreted by astrocytes, D-serine is an important gliotransmitter and is a co-agonist of the glutamate, N-methyl-D-aspartate (NMDA) receptor. D-serine has been shown to enhance the proliferation of neural stem cells in vitro, but its effect on adult neurogenesis in vivo is unknown. Here, we tested the effect of exogenous administration of D-serine on adult neurogenesis in the mouse dentate gyrus. We found that 1 week of treatment with D-serine increased cell proliferation in vivo and in vitro and increased the density of neural stem cells and transit amplifying progenitors. Furthermore, D-serine increased the survival of newborn neurons. Together, these results indicate that D-serine treatment resulted in the improvement of several steps of adult neurogenesis in vivo.
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Affiliation(s)
- Sebastien Sultan
- Department of Fundamental Neurosciences, University of Lausanne Lausanne, Switzerland
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