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Li S, Li X, Lu M, Chen Q, Yao D, Yu X, Li Z, Ge WP, Wang N, Jin J, Wang Y, Liao Y, Luo F, Yan J, Chen X, Jiang C, Yue F, Gao D, Tang X, Guo H, Wang Y, Chen X, Xia J, Xu M, Ren S, He C, Hu Z. Homeostatic Shrinkage of Dendritic Spines Requires Melatonin Type 3 Receptor Activation During Sleep. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2400253. [PMID: 39119847 DOI: 10.1002/advs.202400253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 07/25/2024] [Indexed: 08/10/2024]
Abstract
High-frequency oscillatory activity in cognition-related neural circuits during wakefulness consistently induces the growth of dendritic spines and axonal terminals. Although these structural changes are essential for cognitive functions, it is hypothesized that if these newly expanded structures fail to establish functional connections, they may become superfluous. Sleep is believed to facilitate the reduction of such redundant structures to maintain neural homeostasis. However, the mechanisms underlying this pruning process during sleep remain poorly understood. In this study, that melatonin type 3 receptors (MT3Rs) are selectively expressed in the stellate neurons of the medial entorhinal cortex (MEC) is demonstrated, an area where high melatonin levels are detected during sleep. Activation of MT3Rs during sleep initiates the shrinkage of dendritic spines in stellate neurons by downregulating neural network activity and dephosphorylating synaptic proteins in the MEC. This process is disrupted when MT3R expression is knocked down or when MT3Rs are blocked during sleep. Notably, interference with MT3Rs in the MEC during sleep impairs the acquisition of spatial memory but does not affect object memory acquisition following sleep. These findings reveal novel molecular mechanisms involving melatonin and MT3Rs in the regulation of dendritic spine shrinkage during sleep, which is crucial for the acquisition and consolidation of spatial memory.
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Affiliation(s)
- Shiyin Li
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Xin Li
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
- School of Basic Medical Sciences and IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China
| | - Minmin Lu
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Quanhui Chen
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Di Yao
- School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China
- Chinese Institute for Brain Research, Beijing, 102206, China
| | - Xiaoqian Yu
- Chinese Institute for Brain Research, Beijing, 102206, China
| | - Zhen Li
- Chinese Institute for Brain Research, Beijing, 102206, China
| | - Woo-Ping Ge
- Chinese Institute for Brain Research, Beijing, 102206, China
| | - Na Wang
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Jiehua Jin
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Yaling Wang
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Yixiang Liao
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Fenlan Luo
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Jie Yan
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Xuedan Chen
- Department of Medical Genetics, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038, China
| | - Chenggang Jiang
- Department of Sleep and Psychology, Chongqing Health Center for Women and Children, Chongqing, 401147, China
| | - Faguo Yue
- Sleep and Psychology Center, Bishan Hospital of Chongqing Medical University, Chongqing, 402760, China
| | - Dong Gao
- Department of Sleep and Psychology, The Fifth People's Hospital of Chongqing, Chongqing, 400062, China
| | - Xiangdong Tang
- Sleep Medicine Center, Laboratory of Anaesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Hong Guo
- Department of Medical Genetics, College of Basic Medical Sciences, Third Military Medical University, Chongqing, 400038, China
| | - Yanjiang Wang
- Department of Neurology, Daping Hospital, Third Military Medical University, Chongqing, 400042, China
- Chongqing Institute for Brain and Intelligence, Guangyang Bay Laboratory, Chongqing, 400064, China
| | - Xiaowei Chen
- Chongqing Institute for Brain and Intelligence, Guangyang Bay Laboratory, Chongqing, 400064, China
- Brain Research Center, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Jianxia Xia
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Min Xu
- Institute of Neuroscience,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Shuancheng Ren
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Chao He
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
| | - Zhian Hu
- Department of Physiology, Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400038, China
- Chongqing Institute for Brain and Intelligence, Guangyang Bay Laboratory, Chongqing, 400064, China
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Mey M, Bhatta S, Suresh S, Labrador LM, Piontkivska H, Casadesus G. Therapeutic benefits of central LH receptor agonism in the APP/PS1 AD model involve trophic and immune regulation and are reproductive status dependent. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167165. [PMID: 38653355 DOI: 10.1016/j.bbadis.2024.167165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 04/02/2024] [Accepted: 04/08/2024] [Indexed: 04/25/2024]
Abstract
The mechanisms that underly reproductive hormone effects on cognition, neuronal plasticity, and AD risk, particularly in relation to gonadotropin LH receptor (LHCGR) signaling, remain poorly understood. To address this gap in knowledge and clarify the impact of circulating steroid hormones on the therapeutic effects of CNS LHCGR activation, we delivered the LHCGR agonist human chorionic gonadotropin (hCG) intracerebroventricularly (ICV) and evaluated functional, structural, plasticity-related signaling cascades, Aβ pathology, and transcriptome differences in reproductively intact and ovariectomized (OVX) APP/PS1 AD female mice. Here we demonstrate that CNS hCG delivery restored function to wild-type levels only in OVX APP/PS1 mice. Spine density was increased in all hCG treated groups independently of reproductive status. Notably, increases in BDNF signaling and cognition, were selectively upregulated only in the OVX hCG-treated group. RNA sequencing analyses identified a significant increase in peripheral myeloid and pro-inflammatory genes within the hippocampi of the OVX group that were completely reversed by hCG treatment, identifying a potential mechanism underlying the selective therapeutic effect of LHCGR activation. Interestingly, in intact mice, hCG administration mimicked the effects of gonadectomy. Together, our findings indicate that CNS LHCGR agonism in the post-menopausal context is beneficial through trophic and immune mechanisms. Our findings also underscore the presence of a steroid-LHCGR mechanistic interaction that is unexplored yet potentially meaningful to fully understand "post-menopausal" brain function and CNS hormone treatment response.
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Affiliation(s)
- Megan Mey
- Kent State University, Kent, OH 44240, United States of America
| | - Sabina Bhatta
- Case Western Reserve University, Cleveland, OH 44106, United States of America
| | - Sneha Suresh
- University of Florida, Gainesville, FL 32606, United States of America
| | | | | | - Gemma Casadesus
- University of Florida, Gainesville, FL 32606, United States of America.
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Mey M, Bhatta S, Suresh S, Montero Labrador L, Piontkivska H, Casadesus G. The LH receptor regulates hippocampal spatial memory and restores dendritic spine density in ovariectomized APP/PS1 AD mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573087. [PMID: 38187770 PMCID: PMC10769359 DOI: 10.1101/2023.12.22.573087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Activation of the luteinizing hormone receptor (LHCGR) rescues spatial memory function and spine density losses associated with gonadectomy and high circulating gonadotropin levels in females. However, whether this extends to the AD brain or the mechanisms that underlie these benefits remain unknown. To address this question, we delivered the LHCGR agonist human chorionic gonadotropin (hCG) intracerebroventricularly (ICV), under reproductively intact and ovariectomized conditions to mimic the post-menopausal state in the APP/PS1mouse brain. Cognitive function was tested using the Morris water maze task, and hippocampal dendritic spine density, Aβ pathology, and signaling changes associated with these endpoints were determined to address mechanisms. Here we show that central LHCGR activation restored function in ovariectomized APP/PS1 female mice to wild-type levels without altering Aβ pathology. LHCGR activation increased hippocampal dendritic spine density regardless of reproductive status, and this was mediated by BDNF-dependent and independent signaling. We also show that ovariectomy in the APP/PS1 brain elicits an increase in peripherally derived pro-inflammatory genes which are inhibited by LHCGR activation. This may mediate reproductive status specific effects of LHCGR agonism on cognitive function and BDNF expression. Together, this work highlights the relevance of the LHCGR on cognition and its therapeutic potential in the "menopausal" AD brain.
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Kim JH, Chung KH, Hwang YR, Park HR, Kim HJ, Kim HG, Kim HR. Exposure to RF-EMF Alters Postsynaptic Structure and Hinders Neurite Outgrowth in Developing Hippocampal Neurons of Early Postnatal Mice. Int J Mol Sci 2021; 22:ijms22105340. [PMID: 34069478 PMCID: PMC8159076 DOI: 10.3390/ijms22105340] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 12/23/2022] Open
Abstract
Exposure to radiofrequency electromagnetic fields (RF-EMFs) has increased rapidly in children, but information on the effects of RF-EMF exposure to the central nervous system in children is limited. In this study, pups and dams were exposed to whole-body RF-EMF at 4.0 W/kg specific absorption rate (SAR) for 5 h per day for 4 weeks (from postnatal day (P) 1 to P28). The effects of RF-EMF exposure on neurons were evaluated by using both pups' hippocampus and primary cultured hippocampal neurons. The total number of dendritic spines showed statistically significant decreases in the dentate gyrus (DG) but was not altered in the cornu ammonis (CA1) in hippocampal neurons. In particular, the number of mushroom-type dendritic spines showed statistically significant decreases in the CA1 and DG. The expression of glutamate receptors was decreased in mushroom-type dendritic spines in the CA1 and DG of hippocampal neurons following RF-EMF exposure. The expression of brain-derived neurotrophic factor (BDNF) in the CA1 and DG was significantly lower statistically in RF-EMF-exposed mice. The number of post-synaptic density protein 95 (PSD95) puncta gradually increased over time but was significantly decreased statistically at days in vitro (DIV) 5, 7, and 9 following RF-EMF exposure. Decreased BDNF expression was restricted to the soma and was not observed in neurites of hippocampal neurons following RF-EMF exposure. The length of neurite outgrowth and number of branches showed statistically significant decreases, but no changes in the soma size of hippocampal neurons were observed. Further, the memory index showed statistically significant decreases in RF-EMF-exposed mice, suggesting that decreased synaptic density following RF-EMF exposure at early developmental stages may affect memory function. Collectively, these data suggest that hindered neuronal outgrowth following RF-EMF exposure may decrease overall synaptic density during early neurite development of hippocampal neurons.
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Affiliation(s)
- Ju Hwan Kim
- Department of Pharmacology, College of Medicine, Dankook University, Cheonan 31116, Korea; (J.H.K.); (H.R.P.); (H.-G.K.)
| | - Kyung Hwun Chung
- Hyangseol Medical Research Center, Soonchunhyang University Bucheon Hospital, Bucheon 14584, Korea;
| | - Yeong Ran Hwang
- Department of Physiology, College of Medicine, Dankook University, Cheonan 31116, Korea; (Y.R.H.); (H.J.K.)
| | - Hye Ran Park
- Department of Pharmacology, College of Medicine, Dankook University, Cheonan 31116, Korea; (J.H.K.); (H.R.P.); (H.-G.K.)
| | - Hee Jung Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan 31116, Korea; (Y.R.H.); (H.J.K.)
| | - Hyung-Gun Kim
- Department of Pharmacology, College of Medicine, Dankook University, Cheonan 31116, Korea; (J.H.K.); (H.R.P.); (H.-G.K.)
| | - Hak Rim Kim
- Department of Pharmacology, College of Medicine, Dankook University, Cheonan 31116, Korea; (J.H.K.); (H.R.P.); (H.-G.K.)
- Correspondence: ; Tel.: +82-41-550-3935
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5
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Effects of chronic mild stress induced depression on synaptic plasticity in mouse hippocampus. Behav Brain Res 2019; 365:26-35. [DOI: 10.1016/j.bbr.2019.02.044] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/23/2019] [Accepted: 02/26/2019] [Indexed: 12/11/2022]
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6
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Femi-Akinlosotu OM, Shokunbi MT, Naicker T. Dendritic and Synaptic Degeneration in Pyramidal Neurons of the Sensorimotor Cortex in Neonatal Mice With Kaolin-Induced Hydrocephalus. Front Neuroanat 2019; 13:38. [PMID: 31110476 PMCID: PMC6501759 DOI: 10.3389/fnana.2019.00038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 03/18/2019] [Indexed: 11/13/2022] Open
Abstract
Obstructive hydrocephalus is a brain disorder in which the circulation of cerebrospinal fluid (CSF) is altered in a manner that causes expansion of fluid-filled intracranial compartments particularly the ventricles. The pyramidal neurons of the sensorimotor cortex are excitatory in nature and their dendritic spines are targets of excitatory synapses. This study evaluated the effect of hydrocephalus on dendritic arborization and synaptic structure of the pyramidal neurons of the sensorimotor cortex of neonatal hydrocephalic mice. Sterile kaolin suspension (0.01 ml of 250 mg/mL) was injected intracisternally into day old mice. Control animals mice received sham injections. Pups were weighed and sacrificed on postnatal days (PND) 7, 14 and 21. Fixed brain tissue blocks were silver impregnated using a modified Golgi staining technique and immunolabeled with synaptophysin to determine dendritic morphology and synaptic integrity respectively. Data were analyzed using ANOVA at α 0.05. Golgi staining revealed diminished arborization of the basal dendrites and loss of dendritic spines in the pyramidal neurons of hydrocephalic mice. Compared to age-matched controls, there was a significant reduction in the percentage immunoreactivity of anti-synaptophysin in hydrocephalic mice on PND 7 (14.26 ± 1.91% vs. 62.57 ± 9.40%), PND 14 (4.19 ± 1.57% vs. 93.01 ± 1.66%) and PND 21 (17.55 ± 2.76% vs. 99.11 ± 0.63%) respectively. These alterations suggest impaired neuronal connections that are essential for the development of cortical circuits and may be the structural basis of the neurobehavioral deficits observed in neonatal hydrocephalus.
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Affiliation(s)
| | - Matthew T. Shokunbi
- Department of Anatomy, College of Medicine, University of Ibadan, Ibadan, Nigeria
- Department of Surgery, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Thajasvarie Naicker
- Optics & Imaging Centre, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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Li Y, Zhang Y, Wang W, Zhang Y, Yu Y, Cheing GLY, Pan W. Effects of pulsed electromagnetic fields on learning and memory abilities of STZ-induced dementia rats. Electromagn Biol Med 2019; 38:123-130. [DOI: 10.1080/15368378.2019.1591437] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Yue Li
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Yingchao Zhang
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Weihong Wang
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Yuxia Zhang
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Yang Yu
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Gladys Lai-Ying Cheing
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, SAR, China
| | - Weidong Pan
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
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8
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Modolo J, Thomas AW, Legros A. Human exposure to power frequency magnetic fields up to 7.6 mT: An integrated EEG/fMRI study. Bioelectromagnetics 2017. [PMID: 28628224 DOI: 10.1002/bem.22064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We assessed the effects of power-line frequency (60 Hz in North America) magnetic fields (MF) in humans using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twenty-five participants were enrolled in a pseudo-double-blind experiment involving "real" or "sham" exposure to sinusoidal 60 Hz MF exposures delivered using the gradient coil of an MRI scanner following two conditions: (i) 10 s exposures at 3 mT (10 repetitions); (ii) 2 s exposures at 7.6 mT (100 repetitions). Occipital EEG spectral power was computed in the alpha range (8-12 Hz, reportedly the most sensitive to MF exposure in the literature) with/without exposure. Brain functional activation was studied using fMRI blood oxygen level-dependent (BOLD, inversely correlated with EEG alpha power) maps. No significant effects were detected on occipital EEG alpha power during or post-exposure for any exposure condition. Consistent with EEG results, no effects were observed on fMRI BOLD maps in any brain region. Our results suggest that acute exposure (2-10 s) to 60 Hz MF from 3 to 7.6 mT (30,000 to 76,000 times higher than average public exposure levels for 60 Hz MF) does not induce detectable changes in EEG or BOLD signals. Combined with previous findings in which effects were observed on the BOLD signal after 1 h exposure to 3 mT, 60 Hz MF, this suggests that MF exposure in the low mT range (<10 mT) might require prolonged durations of exposure to induce detectable effects. Bioelectromagnetics. 38:425-435, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Julien Modolo
- Human Threshold Research and Bioelectromagnetics Group, Imaging Program, Lawson Health Research Institute, London, Canada.,Department of Medical Biophysics, Western University, London, Canada.,Department of Medical Imaging, Western University, London, Canada.,Institut National de la Santé et de la Recherche Médicale (INSERM), Rennes, France.,Laboratoire Traitement du Signal et de l'Image (LTSI), University of Rennes 1, LTSI, Rennes, France
| | - Alex W Thomas
- Human Threshold Research and Bioelectromagnetics Group, Imaging Program, Lawson Health Research Institute, London, Canada.,Department of Medical Biophysics, Western University, London, Canada.,Department of Medical Imaging, Western University, London, Canada
| | - Alexandre Legros
- Human Threshold Research and Bioelectromagnetics Group, Imaging Program, Lawson Health Research Institute, London, Canada.,Department of Medical Biophysics, Western University, London, Canada.,Department of Medical Imaging, Western University, London, Canada.,School of Kinesiology, Western University, London, Canada.,EuroMov, University of Montpellier, Montpellier, France
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9
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Effect of 1.8 GHz radiofrequency electromagnetic radiation on novel object associative recognition memory in mice. Sci Rep 2017; 7:44521. [PMID: 28303965 PMCID: PMC5355939 DOI: 10.1038/srep44521] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 02/10/2017] [Indexed: 02/06/2023] Open
Abstract
Mounting evidence suggests that exposure to radiofrequency electromagnetic radiation (RF-EMR) can influence learning and memory in rodents. In this study, we examined the effects of single exposure to 1.8 GHz RF-EMR for 30 min on subsequent recognition memory in mice, using the novel object recognition task (NORT). RF-EMR exposure at an intensity of >2.2 W/kg specific absorption rate (SAR) power density induced a significant density-dependent increase in NORT index with no corresponding changes in spontaneous locomotor activity. RF-EMR exposure increased dendritic-spine density and length in hippocampal and prefrontal cortical neurons, as shown by Golgi staining. Whole-cell recordings in acute hippocampal and medial prefrontal cortical slices showed that RF-EMR exposure significantly altered the resting membrane potential and action potential frequency, and reduced the action potential half-width, threshold, and onset delay in pyramidal neurons. These results demonstrate that exposure to 1.8 GHz RF-EMR for 30 min can significantly increase recognition memory in mice, and can change dendritic-spine morphology and neuronal excitability in the hippocampus and prefrontal cortex. The SAR in this study (3.3 W/kg) was outside the range encountered in normal daily life, and its relevance as a potential therapeutic approach for disorders associated with recognition memory deficits remains to be clarified.
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Yao JJ, Zhao QR, Liu DD, Chow CW, Mei YA. Neuritin Up-regulates Kv4.2 α-Subunit of Potassium Channel Expression and Affects Neuronal Excitability by Regulating the Calcium-Calcineurin-NFATc4 Signaling Pathway. J Biol Chem 2016; 291:17369-81. [PMID: 27307045 PMCID: PMC5016134 DOI: 10.1074/jbc.m115.708883] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Indexed: 11/06/2022] Open
Abstract
Neuritin is an important neurotrophin that regulates neural development, synaptic plasticity, and neuronal survival. Elucidating the downstream molecular signaling is important for potential therapeutic applications of neuritin in neuronal dysfunctions. We previously showed that neuritin up-regulates transient potassium outward current (IA) subunit Kv4.2 expression and increases IA densities, in part by activating the insulin receptor signaling pathway. Molecular mechanisms of neuritin-induced Kv4.2 expression remain elusive. Here, we report that the Ca(2+)/calcineurin (CaN)/nuclear factor of activated T-cells (NFAT) c4 axis is required for neuritin-induced Kv4.2 transcriptional expression and potentiation of IA densities in cerebellum granule neurons. We found that neuritin elevates intracellular Ca(2+) and increases Kv4.2 expression and IA densities; this effect was sensitive to CaN inhibition and was eliminated in Nfatc4(-/-) mice but not in Nfatc2(-/-) mice. Stimulation with neuritin significantly increased nuclear accumulation of NFATc4 in cerebellum granule cells and HeLa cells, which expressed IR. Furthermore, NFATc4 was recruited to the Kv4.2 gene promoter loci detected by luciferase reporter and chromatin immunoprecipitation assays. More importantly, data obtained from cortical neurons following adeno-associated virus-mediated overexpression of neuritin indicated that reduced neuronal excitability and increased formation of dendritic spines were abrogated in the Nfatc4(-/-) mice. Together, these data demonstrate an indispensable role for the CaN/NFATc4 signaling pathway in neuritin-regulated neuronal functions.
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Affiliation(s)
- Jin-Jing Yao
- From the Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China and
| | - Qian-Ru Zhao
- From the Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China and
| | - Dong-Dong Liu
- From the Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China and
| | - Chi-Wing Chow
- the Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York 10461
| | - Yan-Ai Mei
- From the Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China and
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11
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Neuroplastin 65 mediates cognitive functions via excitatory/inhibitory synapse imbalance and ERK signal pathway. Neurobiol Learn Mem 2015; 127:72-83. [PMID: 26691780 DOI: 10.1016/j.nlm.2015.11.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 11/21/2015] [Accepted: 11/28/2015] [Indexed: 01/27/2023]
Abstract
Neuroplastin 65 (NP65) is a brain-specific glycoprotein component of synaptic membrane, which is predominantly located in the forebrain such as the cortex, amygdala and striatum and hippocampus. Previous studies have shown that NP65 is implicated in synaptic plasticity, so it was hypothesized to play roles in cognitive functions. To test this hypothesis, we generated NP65 knock-out (KO) mice and found that the null mice exhibited enhanced hippocampus-dependent learning and memory as manifested by Morris water maze test and step-through passive avoidance test, but showed anxiety-like behaviors as manifested by open field test and light/dark exploration test. In addition, molecular and cellular studies revealed several alterations including: (1) the enhanced ratio of excitatory to inhibitory synapses; (2) increased expression of NMDA receptors NR2A; (3) enhanced activation of ERK signaling; (4) lowered number of the mushroom- and bifurcate-shaped dendritic spines in NP65 KO mice. Together, our findings suggest that NP65 may mediate cognitive functions.
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12
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Yang G, Ren Z, Mei YA. Exposure to 50 Hz magnetic field modulates GABAA currents in cerebellar granule neurons through an EP receptor-mediated PKC pathway. J Cell Mol Med 2015; 19:2413-22. [PMID: 26176998 PMCID: PMC4594682 DOI: 10.1111/jcmm.12626] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/12/2015] [Indexed: 12/31/2022] Open
Abstract
Previous work from both our lab and others have indicated that exposure to 50 Hz magnetic fields (ELF-MF) was able to modify ion channel functions. However, very few studies have investigated the effects of MF on γ-aminobutyric acid (GABA) type A receptors (GABA(A) Rs) channel functioning, which are fundamental to overall neuronal excitability. Here, our major goal is to reveal the potential effects of ELF-MF on GABA(A) Rs activity in rat cerebellar granule neurons (CGNs). Our results indicated that exposing CGNs to 1 mT ELF-MF for 60 min. significantly increased GABA(A) R currents without modifying sensitivity to GABA. However, activation of PKA by db-cAMP failed to do so, but led to a slight decrease instead. On the other hand, PKC activation or inhibition by PMA or Bis and Docosahexaenoic acid (DHA) mimicked or eliminated the field-induced-increase of GABA(A) R currents. Western blot analysis indicated that the intracellular levels of phosphorylated PKC (pPKC) were significantly elevated after 60 min. of ELF-MF exposure, which was subsequently blocked by application of DHA or EP1 receptor-specific (prostaglandin E receptor 1) antagonist (SC19220), but not by EP2-EP4 receptor-specific antagonists. SC19220 also significantly inhibited the ELF-MF-induced elevation on GABA(A) R currents. Together, these data obviously demonstrated for the first time that neuronal GABA(A) currents are significantly increased by ELF-MF exposure, and also suggest that these effects are mediated via an EP1 receptor-mediated PKC pathway. Future work will focus on a more comprehensive analysis of the physiological and/or pathological consequences of these effects.
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Affiliation(s)
- Guang Yang
- School of Life Sciences, Institute of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China
| | - Zhen Ren
- School of Life Sciences, Institute of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China
| | - Yan-Ai Mei
- School of Life Sciences, Institute of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan UniversityShanghai, China
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Gull S, Ingrisch I, Tausch S, Witte OW, Schmidt S. Consistent and reproducible staining of glia by a modified Golgi-Cox method. J Neurosci Methods 2015; 256:141-50. [PMID: 26365333 DOI: 10.1016/j.jneumeth.2015.08.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 08/24/2015] [Accepted: 08/26/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Golgi-Cox staining is a powerful histochemical approach which has been used extensively to visualize the morphology of neurons and glia. However, its usage as a first-choice method is hindered by its uncertain nature, diminished consistency and lengthy staining duration. The FD Rapid GolgiStain™ Kit (FD Neurotechnologies, Inc., USA) has been developed by employing the Golgi-Cox approach. It is a simple, reliable and reproducible way of performing Golgi impregnation for the analysis of neuronal morphology. NEW METHOD We report here simple modifications to the manufacturer's protocol which enable reproducible and reliable staining of glial cells. RESULTS Exposure of brain tissue to 4% paraformaldehyde (PFA) during perfusion followed by postfixation with 8% glutaraldehyde in 4% PFA led to only glial cells being stained, whereas in the absence of postfixation both neurons and glia were stained with unclear morphology. Additionally, we found that impregnation at 26°C±1 was critical to attain uniform staining. COMPARISON WITH EXISTING METHOD Our modified Golgi-Cox approach is consistent and reproducible and affords uniform glial staining throughout the brain. CONCLUSION As this protocol stains only a small percentage of cells, it is suitable for the analysis of individual cells.
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Affiliation(s)
- S Gull
- Hans Berger Department of Neurology, Jena University Hospital, 07747 Jena, Germany
| | - I Ingrisch
- Hans Berger Department of Neurology, Jena University Hospital, 07747 Jena, Germany
| | - S Tausch
- Hans Berger Department of Neurology, Jena University Hospital, 07747 Jena, Germany
| | - O W Witte
- Hans Berger Department of Neurology, Jena University Hospital, 07747 Jena, Germany
| | - S Schmidt
- Hans Berger Department of Neurology, Jena University Hospital, 07747 Jena, Germany.
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Zhao QR, Lu JM, Yao JJ, Zhang ZY, Ling C, Mei YA. Neuritin reverses deficits in murine novel object associative recognition memory caused by exposure to extremely low-frequency (50 Hz) electromagnetic fields. Sci Rep 2015; 5:11768. [PMID: 26138388 PMCID: PMC4650637 DOI: 10.1038/srep11768] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 06/01/2015] [Indexed: 12/21/2022] Open
Abstract
Animal studies have shown that electromagnetic field exposure may interfere with the activity of brain cells, thereby generating behavioral and cognitive disturbances. However, the underlying mechanisms and possible preventions are still unknown. In this study, we used a mouse model to examine the effects of exposure to extremely low-frequency (50 Hz) electromagnetic fields (ELF MFs) on a recognition memory task and morphological changes of hippocampal neurons. The data showed that ELF MFs exposure (1 mT, 12 h/day) induced a time-dependent deficit in novel object associative recognition memory and also decreased hippocampal dendritic spine density. This effect was observed without corresponding changes in spontaneous locomotor activity and was transient, which has only been seen after exposing mice to ELF MFs for 7-10 days. The over-expression of hippocampal neuritin, an activity-dependent neurotrophic factor, using an adeno-associated virus (AAV) vector significantly increased the neuritin level and dendritic spine density. This increase was paralleled with ELF MFs exposure-induced deficits in recognition memory and reductions of dendritic spine density. Collectively, our study provides evidence for the association between ELF MFs exposure, impairment of recognition memory, and resulting changes in hippocampal dendritic spine density. Neuritin prevented this ELF MFs-exposure-induced effect by increasing the hippocampal spine density.
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Affiliation(s)
- Qian-Ru Zhao
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China
| | - Jun-Mei Lu
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China
| | - Jin-Jing Yao
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China
| | - Zheng-Yu Zhang
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China
| | - Chen Ling
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL 32611, USA
| | - Yan-Ai Mei
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200433, China
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Luo FL, Yang N, He C, Li HL, Li C, Chen F, Xiong JX, Hu ZA, Zhang J. Exposure to extremely low frequency electromagnetic fields alters the calcium dynamics of cultured entorhinal cortex neurons. ENVIRONMENTAL RESEARCH 2014; 135:236-246. [PMID: 25462671 DOI: 10.1016/j.envres.2014.09.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/25/2014] [Accepted: 09/13/2014] [Indexed: 06/04/2023]
Abstract
Previous studies have revealed that extremely low frequency electromagnetic field (ELF-EMF) exposure affects neuronal dendritic spine density and NMDAR and AMPAR subunit expressions in the entorhinal cortex (EC). Although calcium signaling has a critical role in control of EC neuronal functions, however, it is still unclear whether the ELF-EMF exposure affects the EC neuronal calcium homeostasis. In the present study, using whole-cell recording and calcium imaging, we record the whole-cell inward currents that contain the voltage-gated calcium currents and show that ELF-EMF (50Hz, 1mT or 3mT, lasting 24h) exposure does not influence these currents. Next, we specifically isolate the high-voltage activated (HVA) and low-voltage activated (LVA) calcium channels-induced currents. Similarly, the activation and inactivation characteristics of these membrane calcium channels are also not influenced by ELF-EMF. Importantly, ELF-EMF exposure reduces the maximum amplitude of the high-K(+)-evoked calcium elevation in EC neurons, which is abolished by thapsigargin, a Ca(2+) ATPase inhibitor, to empty the intracellular calcium stores of EC neurons. Together, these findings indicate that ELF-EMF exposure specifically influences the intracellular calcium dynamics of cultural EC neurons via a calcium channel-independent mechanism.
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Affiliation(s)
- Fen-Lan Luo
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Nian Yang
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Chao He
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Hong-Li Li
- Department of Histology and Embryology, Third Military Medical University, Chongqing 400038, PR China
| | - Chao Li
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Fang Chen
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Jia-Xiang Xiong
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Zhi-An Hu
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
| | - Jun Zhang
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
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16
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Li C, Xie M, Luo F, He C, Wang J, Tan G, Hu Z. The extremely low-frequency magnetic field exposure differently affects the AMPAR and NMDAR subunit expressions in the hippocampus, entorhinal cortex and prefrontal cortex without effects on the rat spatial learning and memory. ENVIRONMENTAL RESEARCH 2014; 134:74-80. [PMID: 25046815 DOI: 10.1016/j.envres.2014.06.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/18/2014] [Accepted: 06/28/2014] [Indexed: 06/03/2023]
Abstract
In the present study, we investigated the effects of chronic exposure (14 and 28 days) to a 50 Hz, 0.5 mT extremely low-frequency magnetic field (ELF-MF) on the NMDAR and AMPAR subunit expressions and rat spatial learning and memory. Using the Western blotting method, we found ELF-MF exposure specifically decreased the expressions of GluA2 in the EC post 28 day exposure and GluA3 of AMPAR subunits in the PFC after 14 day exposure, while it did not affect the AMPAR subunit expression in the hippocampus at both time points. As for NMDAR subunits, 14 day ELF-MF exposure significantly increased the levels of GluN2A and GluN2B in the hippocampus. Moreover, the levels of GluN1 and GluN2A were enhanced in the EC and PFC after two weeks of ELF-MF exposure. Interestingly, 28 day ELF-MF exposure induced a different expression pattern for NMDAR subunits. The increased GluN2A expression observed at 14 day post ELF-MF exposure was recovered after prolonged exposure in the hippocampus and PFC. In the EC, the increased expression of GluN1 achieved to control level and, specifically, a decrease in GluN2A level was observed. Surprisingly, neither 14 nor 28 day ELF-MF did affect the rat spatial reference memory as assessed by water maze. These results indicate that the dynamic and brain-region specific changes in ionotropic glutamate receptor expression induced by ELF-MF are insufficient to influence the rat spatial learning ability.
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Affiliation(s)
- Chao Li
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Meilan Xie
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Fenlan Luo
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Chao He
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Jiali Wang
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Gang Tan
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China
| | - Zhian Hu
- Department of Physiology, Third Military Medical University, Chongqing 400038, PR China.
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