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Bian X, Li M, Lou S. Resistance training boosts lactate transporters and synaptic proteins in insulin-resistance mice. Heliyon 2024; 10:e34425. [PMID: 39082040 PMCID: PMC11284409 DOI: 10.1016/j.heliyon.2024.e34425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 07/09/2024] [Accepted: 07/09/2024] [Indexed: 08/02/2024] Open
Abstract
Background This investigation delineates the influence of resistance training on the expression of synaptic plasticity-related proteins in the hippocampi of insulin-resistant mice and explores the underlying molecular mechanisms. Methods Six-week-old male C57BL/6 J mice were stratified into a control group and a high-fat diet group to induce insulin resistance over a 12-week period. Subsequently, the mice were further divided into sedentary and resistance training cohorts, with the latter engaging in a 12-week ladder-climbing regimen. Post-intervention, blood, and hippocampal specimens were harvested for analytical evaluation. Results In the insulin-resistant mice, elevated blood lactate levels were observed alongside diminished expression of synaptic plasticity-related proteins, monocarboxylate transporters (MCTs), and reduced phosphorylation of protein kinase B (Akt) and mechanistic target of rapamycin (mTOR). In contrast, the expression of eukaryotic translation initiation factor 4 E-binding protein 2 was significantly augmented. Resistance training mitigated insulin resistance, decreased blood lactate levels, and enhanced the expression and phosphorylation of mTOR, regulatory-associated protein of mTOR, MCTs, and synaptic plasticity-related proteins. Conclusions Resistance training mitigates insulin resistance and improves hippocampal synaptic plasticity by normalizing blood lactate levels and enhancing mTOR, MCTs, and synaptic plasticity-related proteins. It may also activate mTORC1 via the PI3K/Akt pathway, promote lactate utilization, and enhance synaptic plasticity proteins, potentially alleviating peripheral insulin resistance. Further research is needed to confirm these mechanisms.
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Affiliation(s)
- Xuepeng Bian
- Department of Rehabilitation, School of International Medical Technology, Shanghai Sanda University, Shanghai, China
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Mingming Li
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Shujie Lou
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
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Li N, Wang H, Liu H, Zhu L, Lyu Z, Qiu J, Zhao T, Ren H, Huang L, Chen S, Hu X, Zhou L. The effects and mechanisms of acupuncture for post-stroke cognitive impairment: progress and prospects. Front Neurosci 2023; 17:1211044. [PMID: 37397457 PMCID: PMC10309044 DOI: 10.3389/fnins.2023.1211044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Stroke is one of the important causes of both disability and death worldwide, which is very common in older adults. Post-stroke cognitive impairment (PSCI) is a common secondary damage of stroke, which is the main cause of long-term disability and decreased quality of life in stroke patients, which brings a heavy burden to society and families. Acupuncture, as one of the oldest and widely used worldwide techniques in Chinese medicine, is recommended by the World Health Organization (WHO) as an alternative and complementary strategy for improving stroke care. This review comprehensively summarizes literature from the last 25 years, showing that acupuncture can exert strong beneficial effect on PSCI. The mechanisms of acupuncture on PSCI involves anti-neuronal apoptosis, promoting synaptic plasticity, alleviating central and peripheral inflammatory reactions, and regulating brain energy metabolism disorders (including improving cerebral blood flow, glucose utilization and mitochondrial structure and function, etc.), etc. The effects and mechanisms of acupuncture on PSCI reviewed in this study provides scientific and reliable evidence for acupuncture application for PSCI.
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Affiliation(s)
- Ningcen Li
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- Binhai New Area Hospital of TCM, Fourth Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Hui Wang
- Xi’an Hospital of Traditional Chinese Medicine, Xi’an, Shanxi, China
| | - Hang Liu
- Acupuncture and Moxibustion Department, Nanchang Hongdu Hospital of Traditional Chinese Medicine, Nanchang, Jiangxi, China
- Acupuncture and Moxibustion Medical Clinical Research Center of Jiangxi Province, Nanchang, Jiangxi, China
| | - Lina Zhu
- Acupuncture and Moxibustion Department, Nanchang Hongdu Hospital of Traditional Chinese Medicine, Nanchang, Jiangxi, China
- Acupuncture and Moxibustion Medical Clinical Research Center of Jiangxi Province, Nanchang, Jiangxi, China
| | - Zhongxi Lyu
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Jiwen Qiu
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Tianyi Zhao
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Haiyan Ren
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Lihong Huang
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Shuangli Chen
- Research Center of Experimental Acupuncture Science, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Xiuwu Hu
- Acupuncture and Moxibustion Department, Nanchang Hongdu Hospital of Traditional Chinese Medicine, Nanchang, Jiangxi, China
- Acupuncture and Moxibustion Medical Clinical Research Center of Jiangxi Province, Nanchang, Jiangxi, China
| | - Liang Zhou
- Acupuncture and Moxibustion Department, Nanchang Hongdu Hospital of Traditional Chinese Medicine, Nanchang, Jiangxi, China
- Acupuncture and Moxibustion Medical Clinical Research Center of Jiangxi Province, Nanchang, Jiangxi, China
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Li JB, Hu XY, Chen MW, Xiong CH, Zhao N, Ge YH, Wang H, Gao XL, Xu NJ, Zhao LX, Yu ZH, Chen HZ, Qiu Y. p85S6K sustains synaptic GluA1 to ameliorate cognitive deficits in Alzheimer's disease. Transl Neurodegener 2023; 12:1. [PMID: 36624510 PMCID: PMC9827685 DOI: 10.1186/s40035-022-00334-w] [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: 07/03/2022] [Accepted: 12/26/2022] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Ribosomal protein S6 kinase 1 (S6K1) is a serine-threonine kinase that has two main isoforms: p70S6K (70-kDa isoform) and p85S6K (85-kDa isoform). p70S6K, with its upstream mammalian target of rapamycin (mTOR), has been shown to be involved in learning and memory and participate in the pathophysiology of Alzheimer's disease (AD). However, the function of p85S6K has long been neglected due to its high similarity to p70S6k. The role of p85S6K in learning and memory is still largely unknown. METHODS We fractionated the postsynaptic densities to illustrate the differential distribution of p85S6K and p70S6K. Coimmunoprecipitation was performed to unveil interactions between p85S6K and the GluA1 subunit of AMPA receptor. The roles of p85S6K in synaptic targeting of GluA1 and learning and memory were evaluated by specific knockdown or overexpression of p85S6K followed by a broad range of methodologies including immunofluorescence, Western blot, in situ proximity ligation assay, morphological staining and behavioral examination. Further, the expression level of p85S6K was measured in brains from AD patients and AD model mice. RESULTS p85S6K, but not p70S6K, was enriched in the postsynaptic densities. Moreover, knockdown of p85S6K resulted in defective spatial and recognition memory. In addition, p85S6K could interact with the GluA1 subunit of AMPA receptor through synapse-associated protein 97 and A-kinase anchoring protein 79/150. Mechanistic studies demonstrated that p85S6K could directly phosphorylate GluA1 at Ser845 and increase the amount of GluA1 in synapses, thus sustaining synaptic function and spine densities. Moreover, p85S6K was found to be specifically decreased in the synaptosomal compartment in the brains of AD patients and AD mice. Overexpression of p85S6K ameliorated the synaptic deficits and cognitive impairment in transgenic AD model mice. CONCLUSIONS These results strongly imply a significant role for p85S6K in maintaining synaptic and cognitive function by interacting with GluA1. The findings provide an insight into the rational targeting of p85S6K as a therapeutic potential for AD.
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Affiliation(s)
- Jia-Bing Li
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Xiao-Yu Hu
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Mu-Wen Chen
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Cai-Hong Xiong
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Na Zhao
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Yan-Hui Ge
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Hao Wang
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Xiao-Ling Gao
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Nan-Jie Xu
- grid.16821.3c0000 0004 0368 8293Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Lan-Xue Zhao
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Zhi-Hua Yu
- grid.16821.3c0000 0004 0368 8293Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025 China
| | - Hong-Zhuan Chen
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. .,Institute of Interdisciplinary Integrative Biomedical Research, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 201210, China.
| | - Yu Qiu
- Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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Hippocampal mTOR Dysregulation and Morphological Changes in Male Rats after Fetal Growth Restriction. Nutrients 2022; 14:nu14030451. [PMID: 35276811 PMCID: PMC8839133 DOI: 10.3390/nu14030451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 02/04/2023] Open
Abstract
Fetal growth restriction (FGR) has been linked to long-term neurocognitive impairment, especially in males. To determine possible underlying mechanisms, we examined hippocampal cellular composition and mTOR signaling of male rat FGR offspring during main brain growth and development (postnatal days (PND) 1 and 12). FGR was either induced by a low-protein diet throughout pregnancy, experimental placental insufficiency by bilateral uterine vessel ligation or intrauterine stress by “sham” operation. Offspring after unimpaired gestation served as common controls. Low-protein diet led to a reduced cell density in the molecular dentate gyrus subregion, while intrauterine surgical stress was associated with increased cell density in the cellular CA2 subregion. Experimental placental insufficiency caused increased mTOR activation on PND 1, whereas intrauterine stress led to mTOR activation on PND 1 and 12. To determine long-term effects, we additionally examined mTOR signaling and Tau phosphorylation, which is altered in neurodegenerative diseases, on PND 180, but did not find any changes among the experimental groups. Our findings suggest that hippocampal cellular proliferation and mTOR signaling are dysregulated in different ways depending on the cause of FGR. While a low-protein diet induced a decreased cell density, prenatal surgical stress caused hyperproliferation, possibly via increased mTOR signaling.
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Unteroberdörster M, Herring A, Bendix I, Lückemann L, Petschulat J, Sure U, Keyvani K, Hetze S, Schedlowski M, Hadamitzky M. Neurobehavioral effects in rats with experimentally induced glioblastoma after treatment with the mTOR-inhibitor rapamycin. Neuropharmacology 2020; 184:108424. [PMID: 33285202 DOI: 10.1016/j.neuropharm.2020.108424] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/26/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022]
Abstract
Psychiatric symptoms as seen in affective and anxiety disorders frequently appear during glioblastoma (GBM) treatment and disease progression, additionally deteriorate patient's daily life routine. These central comorbidities are difficult to recognize and the causes for these effects are unknown. Since overactivation of mechanistic target of rapamycin (mTOR)- signaling is one key driver in GBM growth, the present study aimed at examining in rats with experimentally induced GBM, neurobehavioral consequences during disease progression and therapy. Male Fisher 344 rats were implanted with syngeneic RG2 tumor cells in the right striatum and treated with the mTOR inhibitor rapamycin (3 mg/kg; once daily, for eight days) before behavioral performance, brain protein expression, and blood samples were analyzed. We could show that treatment with rapamycin diminished GBM tumor growth, confirming mTOR-signaling as one key driver for tumor growth. Importantly, in GBM animals' anxiety-like behavior was observed but only after treatment with rapamycin. These behavioral alterations were moreover accompanied by aberrant glucocorticoid receptor, phosphorylated p70 ribosomal S6 kinase alpha (p-p70s6k), and brain derived neurotrophic factor protein expression in the hippocampus and amygdala in the non-tumor-infiltrated hemisphere of the brain. Despite the beneficial effects on GBM tumor growth, our findings indicate that therapy with rapamycin impaired neurobehavioral functioning. This experimental approach has a high translational value. For one, it emphasizes aberrant mTOR functioning as a central feature mechanistically linking complex brain diseases and behavioral disturbances. For another, it highlights the importance of elaborating the cause of unwanted central effects of immunosuppressive and antiproliferative drugs used in transplantation medicine, immunotherapy, and oncology.
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Affiliation(s)
- Meike Unteroberdörster
- Department of Neurosurgery, University Hospital Essen, University of Duisburg-Essen, 45122, Essen, Germany; Department of Neurosurgery, Charité Universitätsmedizin, 10117, Berlin, Germany
| | - Arne Herring
- Institute of Neuropathology, University Hospital Essen, 45122, Essen, Germany
| | - Ivo Bendix
- Department of Pediatrics I/ Neonatology & Experimental Perinatal Neuroscience, University Hospital Essen, University of Duisburg-Essen, 45122, Essen, Germany
| | - Laura Lückemann
- Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University of Duisburg-Essen, 45122, Essen, Germany
| | - Jasmin Petschulat
- Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University of Duisburg-Essen, 45122, Essen, Germany
| | - Ulrich Sure
- Department of Neurosurgery, University Hospital Essen, University of Duisburg-Essen, 45122, Essen, Germany
| | - Kathy Keyvani
- Institute of Neuropathology, University Hospital Essen, 45122, Essen, Germany
| | - Susann Hetze
- Department of Neurosurgery, University Hospital Essen, University of Duisburg-Essen, 45122, Essen, Germany
| | - Manfred Schedlowski
- Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University of Duisburg-Essen, 45122, Essen, Germany; Department of Clinical Neuroscience, Osher Center for Integrative Medicine, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Martin Hadamitzky
- Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University of Duisburg-Essen, 45122, Essen, Germany.
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Yamada S, Kamata T, Nawa H, Sekijima T, Takei N. AMPK activation, eEF2 inactivation, and reduced protein synthesis in the cerebral cortex of hibernating chipmunks. Sci Rep 2019; 9:11904. [PMID: 31417118 PMCID: PMC6695389 DOI: 10.1038/s41598-019-48172-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 07/26/2019] [Indexed: 01/10/2023] Open
Abstract
During hibernation, mammalian cells are exposed to severe environmental stressors such as low temperature, lowered O2 supply, and glucose deficiency. The cellular metabolic rate is markedly reduced for adapting to these conditions. AMP-activated protein kinase (AMPK) senses the cellular energy status and regulates metabolism. Therefore, we examined AMPK signaling in several brain regions and peripheral tissues in hibernating chipmunk. Eukaryotic elongation factor 2 (eEF2) is a downstream target of AMPK. Phosphorylation of eEF2, indicating its inactivation, is enhanced in the cerebral cortex of hibernating chipmunks. The study indicated that the sequential regulation of AMPK-mammalian target of rapamycin complex 1-eEF2 signaling was altered and protein synthesis ability was reduced in the cerebral cortex of hibernating chipmunks.
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Affiliation(s)
- Shintaro Yamada
- Department of Environmental Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata, 951-8585, Japan
| | - Taito Kamata
- Department of Environmental Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata, 951-8585, Japan
| | - Hiroyuki Nawa
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Tsuneo Sekijima
- Department of Environmental Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata, 951-8585, Japan
| | - Nobuyuki Takei
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan.
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Castora FJ. Mitochondrial function and abnormalities implicated in the pathogenesis of ASD. Prog Neuropsychopharmacol Biol Psychiatry 2019; 92:83-108. [PMID: 30599156 DOI: 10.1016/j.pnpbp.2018.12.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 12/20/2018] [Accepted: 12/24/2018] [Indexed: 12/18/2022]
Abstract
Mitochondria are the powerhouse that generate over 90% of the ATP produced in cells. In addition to its role in energy production, the mitochondrion also plays a major role in carbohydrate, fatty acid, amino acid and nucleotide metabolism, programmed cell death (apoptosis), generation of and protection against reactive oxygen species (ROS), immune response, regulation of intracellular calcium ion levels and even maintenance of gut microbiota. With its essential role in bio-energetic as well as non-energetic biological processes, it is not surprising that proper cellular, tissue and organ function is dependent upon proper mitochondrial function. Accordingly, mitochondrial dysfunction has been shown to be directly linked to a variety of medical disorders, particularly neuromuscular disorders and increasing evidence has linked mitochondrial dysfunction to neurodegenerative and neurodevelopmental disorders such as Alzheimer's Disease (AD), Parkinson's Disease (PD), Rett Syndrome (RS) and Autism Spectrum Disorders (ASD). Over the last 40 years there has been a dramatic increase in the diagnosis of ASD and, more recently, an increasing body of evidence indicates that mitochondrial dysfunction plays an important role in ASD development. In this review, the latest evidence linking mitochondrial dysfunction and abnormalities in mitochondrial DNA (mtDNA) to the pathogenesis of autism will be presented. This review will also summarize the results of several recent `approaches used for improving mitochondrial function that may lead to new therapeutic approaches to managing and/or treating ASD.
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Affiliation(s)
- Frank J Castora
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA; Department of Neurology, Eastern Virginia Medical School, Norfolk, VA, USA.
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8
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Zhang ZY, Liu Z, Deng HH, Chen Q. Effects of acupuncture on vascular dementia (VD) animal models: a systematic review and meta-analysis. Altern Ther Health Med 2018; 18:302. [PMID: 30424749 PMCID: PMC6234685 DOI: 10.1186/s12906-018-2345-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/04/2018] [Indexed: 01/01/2023]
Abstract
BACKGROUND Vascular dementia is the second most common type of dementia that causes cognitive dysfunction. Acupuncture, an ancient therapy, has been mentioned for the treatment of vascular dementia in previous studies. This study aimed to evaluate the effects of acupuncture in animal models of vascular dementia. METHODS Experimental animal studies of treating vascular dementia with acupuncture were gathered from Embase, PubMed and Ovid Medline (R) from the dates of the databases' creation to December 2016. We adopted the CAMARADES 10-item checklist to evaluate the quality of the included studies. The Morris water maze test was considered as an outcome measure. The software Stata12.0 was used for the meta-analysis. Heterogeneity was examined using I2 statistics, and we conducted subgroup analyses to determine the causes of heterogeneity for escape latency and duration in original platform. RESULTS Sixteen studies involving 363 animals met the inclusion criteria. The included studies scored between 4 and 8 points, and the mean was 5.44. The results of the meta-analysis indicated remarkable differences with acupuncture on increasing the duration in the former platform quadrant both in EO models (SMD = 1.56, 95% CI: 1.02 ~ 2.11; p < 0.00001) and 2-VO models (SMD 4.29, 95% CI 3.23 ~ 5.35; p < 0.00001) compared with the control groups. CONCLUSIONS Acupuncture may be effective in improving cognitive function in vascular dementia animal models. The mechanisms of acupuncture for vascular dementia are multiple such as anti-apoptosis, antioxidative stress reaction, and metabolism enhancing of glucose and oxygen.
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Abstract
The mechanistic target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that senses and integrates environmental information into cellular regulation and homeostasis. Accumulating evidence has suggested a master role of mTOR signalling in many fundamental aspects of cell biology and organismal development. mTOR deregulation is implicated in a broad range of pathological conditions, including diabetes, cancer, neurodegenerative diseases, myopathies, inflammatory, infectious, and autoimmune conditions. Here, we review recent advances in our knowledge of mTOR signalling in mammalian physiology. We also discuss the impact of mTOR alteration in human diseases and how targeting mTOR function can treat human diseases.
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Affiliation(s)
- Yassine El Hiani
- a Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2, Canada
| | - Emmanuel Eroume-A Egom
- b Jewish General Hospital and Lady Davis Institute for Medical Research, Montreal, QC H3T 1E2, Canada
| | - Xian-Ping Dong
- a Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2, Canada
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The intestinal TORC2 signaling pathway contributes to associative learning in Caenorhabditis elegans. PLoS One 2017; 12:e0177900. [PMID: 28542414 PMCID: PMC5444632 DOI: 10.1371/journal.pone.0177900] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 05/04/2017] [Indexed: 12/25/2022] Open
Abstract
Several types of associative learning are dependent upon the presence or absence of food, and are crucial for the survival of most animals. Target of rapamycin (TOR), a kinase which exists as a component of two complexes, TOR complex 1 (TORC1) and TOR complex 2 (TORC2), is known to act as a nutrient sensor in numerous organisms. However, the in vivo roles of TOR signaling in the nervous system remain largely unclear, partly because its multifunctionality and requirement for survival make it difficult to investigate. Here, using pharmacological inhibitors and genetic analyses, we show that TORC1 and TORC2 contribute to associative learning between salt and food availability in the nematode Caenorhabditis elegans in a process called taste associative learning. Worms migrate to salt concentrations experienced previously during feeding, but they avoid salt concentrations experienced under starvation conditions. Administration of the TOR inhibitor rapamycin causes a behavioral defect after starvation conditioning. Worms lacking either RICT-1 or SINH-1, two TORC2 components, show defects in migration to high salt levels after learning under both fed and starved conditions. We also analyzed the behavioral phenotypes of mutants of the putative TORC1 substrate RSKS-1 (the C. elegans homolog of the mammalian S6 kinase S6K) and the putative TORC2 substrates SGK-1 and PKC-2 (homologs of the serum and glucocorticoid-induced kinase 1, SGK1, and protein kinase C-α, PKC-α, respectively) and found that neuronal RSKS-1 and PKC-2, as well as intestinal SGK-1, are involved in taste associative learning. Our findings shed light on the functions of TOR signaling in behavioral plasticity and provide insight into the mechanisms by which information sensed in the intestine affects the nervous system to modulate food-searching behaviors.
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11
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Mechanisms of acupuncture on vascular dementia-A review of animal studies. Neurochem Int 2016; 107:204-210. [PMID: 28034725 DOI: 10.1016/j.neuint.2016.12.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 11/07/2016] [Accepted: 12/07/2016] [Indexed: 01/14/2023]
Abstract
Vascular dementia (VaD) is the second leading type of dementia after Alzheimer's disease plaguing the aging population. Acupuncture has served as alternative and complementary medicine in the world for a long time and its use for VaD is based on a large body of preclinical and clinical researches. The mechanisms that underlie the protective effects of acupuncture are slowly beginning to be understood. Acupuncture influences multiple aspects of the pathological process of VaD. It improves cognitive function through protecting cerebral neurons from oxidative stress, apoptosis, and neuroinflammation, regulating glucose metabolism and neurotransmitters. Acupuncture may also improve synaptic plasticity and blood vessel function. It is likely that no single factor can explain the protection provided by acupuncture. This review provides a comprehensive overview of established and recent findings in animal-based researches aiming to elucidate the complex mechanisms of acupuncture on VaD.
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Garza-Lombó C, Gonsebatt ME. Mammalian Target of Rapamycin: Its Role in Early Neural Development and in Adult and Aged Brain Function. Front Cell Neurosci 2016; 10:157. [PMID: 27378854 PMCID: PMC4910040 DOI: 10.3389/fncel.2016.00157] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/30/2016] [Indexed: 01/14/2023] Open
Abstract
The kinase mammalian target of rapamycin (mTOR) integrates signals triggered by energy, stress, oxygen levels, and growth factors. It regulates ribosome biogenesis, mRNA translation, nutrient metabolism, and autophagy. mTOR participates in various functions of the brain, such as synaptic plasticity, adult neurogenesis, memory, and learning. mTOR is present during early neural development and participates in axon and dendrite development, neuron differentiation, and gliogenesis, among other processes. Furthermore, mTOR has been shown to modulate lifespan in multiple organisms. This protein is an important energy sensor that is present throughout our lifetime its role must be precisely described in order to develop therapeutic strategies and prevent diseases of the central nervous system. The aim of this review is to present our current understanding of the functions of mTOR in neural development, the adult brain and aging.
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Affiliation(s)
- Carla Garza-Lombó
- Departamento de Medicina Genómica, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México México
| | - María E Gonsebatt
- Departamento de Medicina Genómica, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México México
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13
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Pirbhoy PS, Farris S, Steward O. Synaptic activation of ribosomal protein S6 phosphorylation occurs locally in activated dendritic domains. ACTA ACUST UNITED AC 2016; 23:255-69. [PMID: 27194793 PMCID: PMC4880148 DOI: 10.1101/lm.041947.116] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/07/2016] [Indexed: 01/08/2023]
Abstract
Previous studies have shown that induction of long-term potentiation (LTP) induces phosphorylation of ribosomal protein S6 (rpS6) in postsynaptic neurons, but the functional significance of rpS6 phosphorylation is poorly understood. Here, we show that synaptic stimulation that induces perforant path LTP triggers phosphorylation of rpS6 (p-rpS6) locally near active synapses. Using antibodies specific for phosphorylation at different sites (ser235/236 versus ser240/244), we show that strong synaptic activation led to dramatic increases in immunostaining throughout postsynaptic neurons with selectively higher staining for p-ser235/236 in the activated dendritic lamina. Following LTP induction, phosphorylation at ser235/236 was detectable by 5 min, peaked at 30 min, and was maintained for hours. Phosphorylation at both sites was completely blocked by local infusion of the NMDA receptor antagonist, APV. Despite robust induction of p-rpS6 following high frequency stimulation, assessment of protein synthesis by autoradiography revealed no detectable increases. Exploration of a novel environment led to increases in the number of p-rpS6-positive neurons throughout the forebrain in a pattern reminiscent of immediate early gene induction and many individual neurons that were p-rpS6-positive coexpressed Arc protein. Our results constrain hypotheses about the possible role of rpS6 phosphorylation in regulating postsynaptic protein synthesis during induction of synaptic plasticity.
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Affiliation(s)
- Patricia Salgado Pirbhoy
- Reeve-Irvine Research Center, Center for the Neurobiology of Learning and Memory Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory
| | - Shannon Farris
- Reeve-Irvine Research Center, Center for the Neurobiology of Learning and Memory Department of Anatomy and Neurobiology, University of California, Irvine, California 92697, USA
| | - Oswald Steward
- Reeve-Irvine Research Center, Center for the Neurobiology of Learning and Memory Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory Department of Anatomy and Neurobiology, University of California, Irvine, California 92697, USA Department of Neurosurgery, University of California, Irvine, California 92697, USA
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14
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Orlovsky M, Dosenko V, Spiga F, Skibo G, Lightman S. Hippocampus remodeling by chronic stress accompanied by GR, proteasome and caspase-3 overexpression. Brain Res 2014; 1593:83-94. [DOI: 10.1016/j.brainres.2014.09.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 09/23/2014] [Accepted: 09/24/2014] [Indexed: 12/31/2022]
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15
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Mechanisms underlying the effect of acupuncture on cognitive improvement: a systematic review of animal studies. J Neuroimmune Pharmacol 2014; 9:492-507. [PMID: 24903518 DOI: 10.1007/s11481-014-9550-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/22/2014] [Indexed: 01/23/2023]
Abstract
Acupuncture has been reported to be beneficial in treating cognitive impairment in various pathological conditions. This review describes the effort to understand the signaling pathways that underlie the acupunctural therapeutic effect on cognitive function. We searched the literature in 12 electronic databases from their inception to November 2013, with full text available and language limited to English. Twenty-three studies were identified under the selection criteria. All recruited animal studies demonstrate a significant positive effect of acupuncture on cognitive impairment. Findings suggest acupuncture may improve cognitive function through modulation of signaling pathways involved in neuronal survival and function, specifically, through promoting cholinergic neural transmission, facilitating dopaminergic synaptic transmission, enhancing neurotrophin signaling, suppressing oxidative stress, attenuating apoptosis, regulating glycometabolic enzymes and reducing microglial activation. However, the quality of reviewed studies has room for improvement. Further high-quality animal studies with randomization, blinding and estimation of sample size are needed to strengthen the recognition of group differences.
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16
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Yasuda S, Sugiura H, Katsurabayashi S, Shimada T, Tanaka H, Takasaki K, Iwasaki K, Kobayashi T, Hino O, Yamagata K. Activation of Rheb, but not of mTORC1, impairs spine synapse morphogenesis in tuberous sclerosis complex. Sci Rep 2014; 4:5155. [PMID: 24889507 PMCID: PMC4042127 DOI: 10.1038/srep05155] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 05/15/2014] [Indexed: 12/30/2022] Open
Abstract
Mutations in the Tsc1 or Tsc2 genes cause tuberous sclerosis complex (TSC). Tsc1 and Tsc2 proteins form a complex that inhibits mammalian target of rapamycin complex 1 (mTORC1) signalling through Rheb-GTPase. We found that Tsc2+/− neurons showed impaired spine synapse formation, which was resistant to an mTORC1 inhibitor. Knockdown of mTOR also failed to restore these abnormalities, suggesting mTORC may not participate in impaired spinogenesis in Tsc2+/− neurons. To address whether Rheb activation impairs spine synapse formation, we expressed active and inactive forms of Rheb in WT and Tsc2+/− neurons, respectively. Expression of active Rheb abolished dendritic spine formation in WT neurons, whereas inactive Rheb restored spine synapse formation in Tsc2+/− neurons. Moreover, inactivation of Rheb with farnesyl transferase inhibitors recovered spine synapse morphogenesis in Tsc2+/− neurons. In conclusion, dendritic spine abnormalities in TSC neurons may be caused through activation of Rheb, but not through of mTORC1.
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Affiliation(s)
- Shin Yasuda
- 1] Neural Plasticity Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan [2]
| | - Hiroko Sugiura
- 1] Neural Plasticity Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan [2]
| | - Shutaro Katsurabayashi
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Tadayuki Shimada
- Neural Plasticity Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hidekazu Tanaka
- Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Shiga, Japan
| | - Kotaro Takasaki
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Katsunori Iwasaki
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | - Toshiyuki Kobayashi
- Department of Pathology and Oncology, Juntendo University, School of Medicine, Tokyo, Japan
| | - Okio Hino
- Department of Pathology and Oncology, Juntendo University, School of Medicine, Tokyo, Japan
| | - Kanato Yamagata
- Neural Plasticity Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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17
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Bergeron Y, Chagniel L, Bureau G, Massicotte G, Cyr M. mTOR signaling contributes to motor skill learning in mice. Front Mol Neurosci 2014; 7:26. [PMID: 24772063 PMCID: PMC3982074 DOI: 10.3389/fnmol.2014.00026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/19/2014] [Indexed: 01/10/2023] Open
Abstract
The mammalian target of rapamycin (mTOR) kinase is a critical regulator of mRNA translation and is suspected to be involved in various long-lasting forms of synaptic and behavioral plasticity. However, its role in motor learning and control has never been examined. This study investigated, in mice, the implication of mTOR in the learning processes associated with the accelerating rotarod task. We first observed that the rotarod learning did not alter the levels of total mTOR in the striatum, hippocampus, cerebellum, and anterior cortex of trained mice. However, it increased the levels of phosphorylated mTOR in the striatum and hippocampus exclusively during the first session of training; no change was observed at the second and third sessions. In order to further investigate the potential role of mTOR during motor skill learning, we performed systemic and intrastriatal inhibitions of mTOR using the pharmacological inhibitor rapamycin, as well as a genetic knockdown of striatal mTOR using intrastriatal infusion of mTOR siRNA. These three independent approaches were all associated with a significant reduction in rotarod performances that were reminiscent of impaired consolidation processes. Notably, these treatments did not affect the capacity of mice to execute the pole test, suggesting that mTOR activity was mainly controlling motor learning rather than motor abilities. Moreover, all treatments decreased the levels of phosphorylated 4EBP1 and P70S6K, two molecular downstream targets of mTORC1. Our findings demonstrate that striatal mTOR kinase, via the phosphorylation of 4EBP1 and P70S6K, plays an important role in the cellular and molecular processes involved in motor skill learning.
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Affiliation(s)
- Yan Bergeron
- Groupe de Recherche en Neurosciences, Département de Biologie Médicale, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
| | - Laure Chagniel
- Groupe de Recherche en Neurosciences, Département de Biologie Médicale, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
| | - Geneviève Bureau
- Groupe de Recherche en Neurosciences, Département de Biologie Médicale, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
| | - Guy Massicotte
- Groupe de Recherche en Neurosciences, Département de Biologie Médicale, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
| | - Michel Cyr
- Groupe de Recherche en Neurosciences, Département de Biologie Médicale, Université du Québec à Trois-Rivières Trois-Rivières, QC, Canada
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18
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Mechanisms of action of brain insulin against neurodegenerative diseases. J Neural Transm (Vienna) 2014; 121:611-26. [PMID: 24398779 DOI: 10.1007/s00702-013-1147-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 12/17/2013] [Indexed: 12/13/2022]
Abstract
Insulin, a pancreatic hormone, is best known for its peripheral effects on the metabolism of glucose, fats and proteins. There is a growing body of evidence linking insulin action in the brain to neurodegenerative diseases. Insulin present in central nervous system is a regulator of central glucose metabolism nevertheless this glucoregulation is not the main function of insulin in the brain. Brain is known to be specifically vulnerable to oxidative products relative to other organs and altered brain insulin signaling may cause or promote neurodegenerative diseases which invalidates and reduces the quality of life. Insulin located within the brain is mostly of pancreatic origin or is produced in the brain itself crosses the blood-brain barrier and enters the brain via a receptor-mediated active transport system. Brain Insulin, insulin receptor and insulin receptor substrate-mediated signaling pathways play important roles in the regulation of peripheral metabolism, feeding behavior, memory and maintenance of neural functions such as neuronal growth and differentiation, neuromodulation and neuroprotection. In the present review, we would like to summarize the novel biological and pathophysiological roles of neuronal insulin in neurodegenerative diseases and describe the main signaling pathways in use for therapeutic strategies in the use of insulin to the cerebral tissues and their biological applications to neurodegenerative diseases.
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19
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Ishizuka Y, Kakiya N, Witters LA, Oshiro N, Shirao T, Nawa H, Takei N. AMP-activated protein kinase counteracts brain-derived neurotrophic factor-induced mammalian target of rapamycin complex 1 signaling in neurons. J Neurochem 2013; 127:66-77. [PMID: 23841933 DOI: 10.1111/jnc.12362] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 07/04/2013] [Accepted: 07/05/2013] [Indexed: 12/20/2022]
Abstract
Growth factors and nutrients, such as amino acids and glucose, regulate mammalian target of rapamycin complex 1 (mTORC1) signaling and subsequent translational control in a coordinated manner. Brain-derived neurotrophic factor (BDNF), the most prominent neurotrophic factor in the brain, activates mTORC1 and induces phosphorylation of its target, p70S6 kinase (p70S6K), at Thr389 in neurons. BDNF also increases mammalian target of rapamycin-dependent novel protein synthesis in neurons. Here, we report that BDNF-induced p70S6K activation is dependent on glucose, but not amino acids, sufficiency in cultured cortical neurons. AMP-activated protein kinase (AMPK) is the molecular background to this specific nutrient dependency. Activation of AMPK, which is induced by glucose deprivation, treatment with pharmacological agents such as 2-deoxy-D-glucose, metformin, and 5-aminoimidazole-4-carboxamide ribonucleoside or forced expression of a constitutively active AMPKα subunit, counteracts BDNF-induced phosphorylation of p70S6K and enhanced protein synthesis in cortical neurons. These results indicate that AMPK inhibits the effects of BDNF on mTORC1-mediated translation in neurons.
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Affiliation(s)
- Yuta Ishizuka
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan; Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Gunma, Japan
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20
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Beck B, Pourié G. Ghrelin, neuropeptide Y, and other feeding-regulatory peptides active in the hippocampus: role in learning and memory. Nutr Rev 2013; 71:541-61. [PMID: 23865799 DOI: 10.1111/nure.12045] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The hippocampus is a brain region of primary importance for neurogenesis, which occurs during early developmental states as well as during adulthood. Increases in neuronal proliferation and in neuronal death with age have been associated with drastic changes in memory and learning. Numerous neurotransmitters are involved in these processes, and some neuropeptides that mediate neurogenesis also modulate feeding behavior. Concomitantly, feeding peptides, which act primarily in the hypothalamus, are also present in the hippocampus. This review aims to ascertain the role of several important feeding peptides in cognitive functions, either through their local synthesis in the hippocampus or through their actions via specific receptors in the hippocampus. A link between neurogenesis and the orexigenic or anorexigenic properties of feeding peptides is discussed.
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Affiliation(s)
- Bernard Beck
- INSERM U954, Nutrition, Génétique et Expositions aux Risques Environnementaux, Faculté de Médecine, Vandœuvre, France.
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21
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Feliciano DM, Lin TV, Hartman NW, Bartley CM, Kubera C, Hsieh L, Lafourcade C, O'Keefe RA, Bordey A. A circuitry and biochemical basis for tuberous sclerosis symptoms: from epilepsy to neurocognitive deficits. Int J Dev Neurosci 2013; 31:667-78. [PMID: 23485365 DOI: 10.1016/j.ijdevneu.2013.02.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/15/2013] [Accepted: 02/18/2013] [Indexed: 01/17/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant monogenetic disorder that is characterized by the formation of benign tumors in several organs as well as brain malformations and neuronal defects. TSC is caused by inactivating mutations in one of two genes, TSC1 and TSC2, resulting in increased activity of the mammalian Target of Rapamycin (mTOR). Here, we explore the cytoarchitectural and functional CNS aberrations that may account for the neurological presentations of TSC, notably seizures, hydrocephalus, and cognitive and psychological impairments. In particular, recent mouse models of brain lesions are presented with an emphasis on using electroporation to allow the generation of discrete lesions resulting from loss of heterozygosity during perinatal development. Cortical lesions are thought to contribute to epileptogenesis and worsening of cognitive defects. However, it has recently been suggested that being born with a mutant allele without loss of heterozygosity and associated cortical lesions is sufficient to generate cognitive and neuropsychiatric problems. We will thus discuss the function of mTOR hyperactivity on neuronal circuit formation and the potential consequences of being born heterozygous on neuronal function and the biochemistry of synaptic plasticity, the cellular substrate of learning and memory. Ultimately, a major goal of TSC research is to identify the cellular and molecular mechanisms downstream of mTOR underlying the neurological manifestations observed in TSC patients and identify novel therapeutic targets to prevent the formation of brain lesions and restore neuronal function.
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Affiliation(s)
- David M Feliciano
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
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22
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Effect of electroacupuncture on the expression of mTOR and eIF4E in hippocampus of rats with vascular dementia. Neurol Sci 2012; 34:1093-7. [PMID: 23053837 DOI: 10.1007/s10072-012-1209-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 09/28/2012] [Indexed: 12/18/2022]
Abstract
Clinically, electroacupuncture is proved to be an effective therapy for vascular dementia; however, their mechanisms remain uncertain. The aim of the current study was to investigate the mechanism of electroacupuncture therapy for vascular dementia. One month after a vascular dementia animal model was established by bilateral occlusion of common carotid arteries, electroacupuncture treatment was given at "Baihui" (DU20), "Dazhui" (DU14), and "Shenshu" (BL23). Morris water maze was used to assess the learning and memory ability of rats. Western blot assay was performed to detect the expression of mammalian target of rapamycin (mTOR) and eukaryotic translation initiation factor 4E (eIF4E) in hippocampus of rats. Morris water maze test showed that electroacupuncture improved the learning ability of vascular dementia rats. Western blot assay revealed that the expression level of mTOR and eIF4E in the electroacupuncture group and sham-operated group was higher than that in the vascular dementia group (P < 0.05). In conclusion, the decreasing expression of mTOR and eIF4E plays important roles in the pathogenesis of vascular dementia. Electroacupuncture improves learning and memory ability by up-regulating expression of mTOR and eIF4E in the hippocampus of vascular dementia rats.
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23
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Moon IS, Lee HJ, Park IS. Dendritic eIF4E-binding protein 1 (eIF4E-BP1) mRNA is upregulated by neuronal activation. J Korean Med Sci 2012; 27:1241-7. [PMID: 23091324 PMCID: PMC3468763 DOI: 10.3346/jkms.2012.27.10.1241] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 08/10/2012] [Indexed: 01/04/2023] Open
Abstract
Long-term synaptic plasticity requires addition of new proteins at the synaptic site. The local protein synthesis at subsynaptic sites confers advantageous mechanisms that would regulate the protein composition in local domains on a moment-by-moment basis. However, our information on the identities of 'dendritic' mRNAs is very limited. In this study we investigated the expression of the protein and mRNA for eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4EBP1) in cultured rat hippocampal neurons. Immunocytochemistry (ICC) showed that 4EBP1 protein is highly localized to the nucleus. In dendrites most 4EBP1 punctae were not colocalized with those of eIF4E. In situ hybridization (ISH) and Fluorescence ISH (FISH) revealed that 4EBP1 mRNA was present in dendrites. The FISH signals formed clusters along dendrites that colocalized with ICC signals for Staufen, a marker for RNA granules. The neuronal activation by KCl (60 mM, 10 min) significantly increased the density of 4EBP1 FISH signals in the nucleus after 2 hr, and both in the nucleus and dendrites after 6 hr. Our results indicate that 4EBP1 and its mRNA are present in dendrites, and the mRNA is upregulated and transported to dendritic domains in RNA granules upon neuronal activation.
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Affiliation(s)
- Il Soo Moon
- Department of Anatomy, Dongguk University College of Medicine, and Medical Institute of Dongguk University, Gyeongju, Korea.
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24
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Polman JAE, Hunter RG, Speksnijder N, van den Oever JME, Korobko OB, McEwen BS, de Kloet ER, Datson NA. Glucocorticoids modulate the mTOR pathway in the hippocampus: differential effects depending on stress history. Endocrinology 2012; 153:4317-27. [PMID: 22778218 DOI: 10.1210/en.2012-1255] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glucocorticoid (GC) hormones, released by the adrenals in response to stress, are key regulators of neuronal plasticity. In the brain, the hippocampus is a major target of GC, with abundant expression of the GC receptor. GC differentially affect the hippocampal transcriptome and consequently neuronal plasticity in a subregion-specific manner, with consequences for hippocampal information flow and memory formation. Here, we show that GC directly affect the mammalian target of rapamycin (mTOR) signaling pathway, which plays a central role in translational control and has long-lasting effects on the plasticity of specific brain circuits. We demonstrate that regulators of the mTOR pathway, DNA damage-induced transcript (DDIT)4 and FK506-binding protein 51 are transcriptionally up-regulated by an acute GC challenge in the dentate gyrus (DG) subregion of the rat hippocampus, most likely via a GC-response element-driven mechanism. Furthermore, two other mTOR pathway members, the mTOR regulator DDIT4-like and the mTOR target DDIT3, are down-regulated by GC in the rat DG. Interestingly, the GC responsiveness of DDIT4 and DDIT3 was lost in animals with a recent history of chronic stress. Basal hippocampal mTOR protein levels were higher in animals exposed to chronic stress than in controls. Moreover, an acute GC challenge significantly reduced mTOR protein levels in the hippocampus of animals with a chronic stress history but not in unstressed controls. Based on these findings, we propose that direct regulation of the mTOR pathway by GC represents an important mechanism regulating neuronal plasticity in the rat DG, which changes after exposure to chronic stress.
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Affiliation(s)
- J Annelies E Polman
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, 2300 RA Leiden, The Netherlands
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25
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Mammalian target of rapamycin: A valid therapeutic target through the autophagy pathway for alzheimer's disease? J Neurosci Res 2012; 90:1105-18. [DOI: 10.1002/jnr.23011] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 10/28/2011] [Accepted: 11/18/2011] [Indexed: 12/15/2022]
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26
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Combination therapy targeting Akt and mammalian target of rapamycin improves functional outcome after controlled cortical impact in mice. J Cereb Blood Flow Metab 2012; 32:330-40. [PMID: 21934697 PMCID: PMC3272599 DOI: 10.1038/jcbfm.2011.131] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Akt and mammalian target of rapamycin (mTOR) are both activated after traumatic brain injury (TBI), however complex interplay between the two hampers deciphering their functional implications in vivo. We examined the effects of single and combination inhibitors of Akt/mTOR in a mouse controlled cortical impact (CCI) model. Following CCI, phospho-Akt-473 (p-Akt) and -S6 ribosomal protein (p-S6RP), a downstream substrate of mTOR, were increased in cortical and hippocampal brain homogenates (P<0.05 versus sham). At 24 hours, p-S6RP was detected in neurons and was robustly induced in microglia and astrocytes in injured hippocampus. In vivo activity of Akt and mTOR inhibitors administered separately was confirmed by reduced expression of p-GSK3β (P<0.01) or p-S6RP (P<0.05), respectively, after CCI. Importantly, administration of Akt and mTOR inhibitors together (but not of either alone) improved postinjury motor (P=0.02) and cognitive deficits (hidden platform trials, P=0.001; probe trials, P<0.05), decreased propidium iodide-positive cells in CA1 and CA3 (P<0.005), and unexpectedly increased p-GSK3β in hippocampus. Although the roles of Akt and mTOR in the pathogenesis of TBI remain to be fully elucidated, dual inhibition of Akt and mTOR may have therapeutic potential for TBI.
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27
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Deli A, Schipany K, Rosner M, Höger H, Pollak A, Li L, Hengstschläger M, Lubec G. Blocking mTORC1 activity by rapamycin leads to impairment of spatial memory retrieval but not acquisition in C57BL/6J mice. Behav Brain Res 2012; 229:320-4. [PMID: 22306200 DOI: 10.1016/j.bbr.2012.01.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 01/02/2012] [Accepted: 01/06/2012] [Indexed: 12/31/2022]
Abstract
Although the involvement of the mTOR (mammalian target of rapamycin) system in memory processes has been reported, information on the effect of rapamycin on spatial learning and memory is limited. It was therefore the aim of the study to show the effect of parenteral rapamycin administration to C57BL/6J mice on performance in the multiple T-maze (MTM) and to determine hippocampal mTOR activity. Rapamycin-treated and -untreated/trained/probed mice are the main part of the experiment considering retrieval and acquisition or consolidation of spatial memory. Six hours following euthanasia hippocampi were extirpated and used for evaluation of mTOR activity as represented by hippocampal levels of S6 protein and its phosphorylated active form (phospho S6 protein, S240,244), a read out of mTOR complex 1 activity. Mice given i.p. rapamycin learned the task of the MTM but failed at the probe trial, showing absence of the phosphorylated active form of S6 protein, indicating inhibition of mTOR activity. Herein, impairing effects of rapamycin on retrieval but not on acquisition or consolidation of spatial memory are shown. Deficient memory retrieval was paralleled by inhibition of mTOR complex 1 activity. The current study extends knowledge on rapamycin in memory mechanisms and challenges work on deeper insights into the role of mTOR in different phases of memory formation and retrieval.
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Affiliation(s)
- Alev Deli
- Department of Pediatrics, Medical University of Vienna, Währinger Gürtel 18, 1090 Vienna, Austria
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28
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Harvard C, Strong E, Mercier E, Colnaghi R, Alcantara D, Chow E, Martell S, Tyson C, Hrynchak M, McGillivray B, Hamilton S, Marles S, Mhanni A, Dawson AJ, Pavlidis P, Qiao Y, Holden JJ, Lewis SME, O'Driscoll M, Rajcan-Separovic E. Understanding the impact of 1q21.1 copy number variant. Orphanet J Rare Dis 2011; 6:54. [PMID: 21824431 PMCID: PMC3180300 DOI: 10.1186/1750-1172-6-54] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Accepted: 08/08/2011] [Indexed: 01/10/2023] Open
Abstract
Background 1q21.1 Copy Number Variant (CNV) is associated with a highly variable phenotype ranging from congenital anomalies, learning deficits/intellectual disability (ID), to a normal phenotype. Hence, the clinical significance of this CNV can be difficult to evaluate. Here we described the consequences of the 1q21.1 CNV on genome-wide gene expression and function of selected candidate genes within 1q21.1 using cell lines from clinically well described subjects. Methods and Results Eight subjects from 3 families were included in the study: six with a 1q21.1 deletion and two with a 1q21.1 duplication. High resolution Affymetrix 2.7M array was used to refine the 1q21.1 CNV breakpoints and exclude the presence of secondary CNVs of pathogenic relevance. Whole genome expression profiling, studied in lymphoblast cell lines (LBCs) from 5 subjects, showed enrichment of genes from 1q21.1 in the top 100 genes ranked based on correlation of expression with 1q21.1 copy number. The function of two top genes from 1q21.1, CHD1L/ALC1 and PRKAB2, was studied in detail in LBCs from a deletion and a duplication carrier. CHD1L/ALC1 is an enzyme with a role in chromatin modification and DNA damage response while PRKAB2 is a member of the AMP kinase complex, which senses and maintains systemic and cellular energy balance. The protein levels for CHD1L/ALC1 and PRKAB2 were changed in concordance with their copy number in both LBCs. A defect in chromatin remodeling was documented based on impaired decatenation (chromatid untangling) checkpoint (DCC) in both LBCs. This defect, reproduced by CHD1L/ALC1 siRNA, identifies a new role of CHD1L/ALC1 in DCC. Both LBCs also showed elevated levels of micronuclei following treatment with a Topoisomerase II inhibitor suggesting increased DNA breaks. AMP kinase function, specifically in the deletion containing LBCs, was attenuated. Conclusion Our studies are unique as they show for the first time that the 1q21.1 CNV not only causes changes in the expression of its key integral genes, associated with changes at the protein level, but also results in changes in their known function, in the case of AMPK, and newly identified function such as DCC activation in the case of CHD1L/ALC1. Our results support the use of patient lymphoblasts for dissecting the functional sequelae of genes integral to CNVs in carrier cell lines, ultimately enhancing understanding of biological processes which may contribute to the clinical phenotype.
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Affiliation(s)
- Chansonette Harvard
- Child and Family Research Institute, Molecular Cytogenetics and Array Laboratory, 950 West 28th Avenue, Vancouver, BC, Canada
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Gafford GM, Parsons RG, Helmstetter FJ. Consolidation and reconsolidation of contextual fear memory requires mammalian target of rapamycin-dependent translation in the dorsal hippocampus. Neuroscience 2011; 182:98-104. [PMID: 21439355 PMCID: PMC3087706 DOI: 10.1016/j.neuroscience.2011.03.023] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 03/02/2011] [Accepted: 03/09/2011] [Indexed: 12/26/2022]
Abstract
The mammalian target of rapamycin (mTOR) pathway is important for regulating protein translation. The present study characterized the role of mTOR-dependent translation in the dorsal hippocampus (DH) during the consolidation and reconsolidation of contextual fear memory. We first showed that fear conditioning resulted in increased phosphorylation of p70s6 kinase (p70s6K) in the DH and that infusion of the mTOR inhibitor rapamycin (RAP) into the DH immediately after training disrupted formation of long-term contextual fear memory. Additionally we showed that p70s6K was activated after retrieval of a previously stored fear memory, and inhibition of mTOR by DH infusion of RAP blocked the reconsolidation of contextual fear memory. Together these results demonstrate that within the DH translational control through the mTOR pathway is important for consolidation as well as the stability of fear memory after retrieval.
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Affiliation(s)
- G M Gafford
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.
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