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Ji Y, Yang C, Pang X, Yan Y, Wu Y, Geng Z, Hu W, Hu P, Wu X, Wang K. Repetitive transcranial magnetic stimulation in Alzheimer's disease: effects on neural and synaptic rehabilitation. Neural Regen Res 2025; 20:326-342. [PMID: 38819037 DOI: 10.4103/nrr.nrr-d-23-01201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/13/2023] [Indexed: 06/01/2024] Open
Abstract
Alzheimer's disease is a neurodegenerative disease resulting from deficits in synaptic transmission and homeostasis. The Alzheimer's disease brain tends to be hyperexcitable and hypersynchronized, thereby causing neurodegeneration and ultimately disrupting the operational abilities in daily life, leaving patients incapacitated. Repetitive transcranial magnetic stimulation is a cost-effective, neuro-modulatory technique used for multiple neurological conditions. Over the past two decades, it has been widely used to predict cognitive decline; identify pathophysiological markers; promote neuroplasticity; and assess brain excitability, plasticity, and connectivity. It has also been applied to patients with dementia, because it can yield facilitatory effects on cognition and promote brain recovery after a neurological insult. However, its therapeutic effectiveness at the molecular and synaptic levels has not been elucidated because of a limited number of studies. This study aimed to characterize the neurobiological changes following repetitive transcranial magnetic stimulation treatment, evaluate its effects on synaptic plasticity, and identify the associated mechanisms. This review essentially focuses on changes in the pathology, amyloidogenesis, and clearance pathways, given that amyloid deposition is a major hypothesis in the pathogenesis of Alzheimer's disease. Apoptotic mechanisms associated with repetitive transcranial magnetic stimulation procedures and different pathways mediating gene transcription, which are closely related to the neural regeneration process, are also highlighted. Finally, we discuss the outcomes of animal studies in which neuroplasticity is modulated and assessed at the structural and functional levels by using repetitive transcranial magnetic stimulation, with the aim to highlight future directions for better clinical translations.
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Affiliation(s)
- Yi Ji
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
| | - Chaoyi Yang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
| | - Xuerui Pang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
| | - Yibing Yan
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
| | - Yue Wu
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
| | - Zhi Geng
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
| | - Wenjie Hu
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
| | - Panpan Hu
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei, Anhui Province, China
| | - Xingqi Wu
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
- Collaborative Innovation Center of Neuropsychiatric Disorders and Mental Health, Hefei, Anhui Province, China
| | - Kai Wang
- Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
- Anhui Province Key Laboratory of Cognition and Neuropsychiatric Disorders, Hefei, Anhui Province, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, Anhui Province, China
- Department of Psychology and Sleep Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
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Heuer SE, Bloss EB, Howell GR. Strategies to dissect microglia-synaptic interactions during aging and in Alzheimer's disease. Neuropharmacology 2024; 254:109987. [PMID: 38705570 DOI: 10.1016/j.neuropharm.2024.109987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 05/07/2024]
Abstract
Age is the largest risk factor for developing Alzheimer's disease (AD), a neurodegenerative disorder that causes a progressive and severe dementia. The underlying cause of cognitive deficits seen in AD is thought to be the disconnection of neural circuits that control memory and executive functions. Insight into the mechanisms by which AD diverges from normal aging will require identifying precisely which cellular events are driven by aging and which are impacted by AD-related pathologies. Since microglia, the brain-resident macrophages, are known to have critical roles in the formation and maintenance of neural circuits through synaptic pruning, they are well-positioned to modulate synaptic connectivity in circuits sensitive to aging or AD. In this review, we provide an overview of the current state of the field and on emerging technologies being employed to elucidate microglia-synaptic interactions in aging and AD. We also discuss the importance of leveraging genetic diversity to study how these interactions are shaped across more realistic contexts. We propose that these approaches will be essential to define specific aging- and disease-relevant trajectories for more personalized therapeutics aimed at reducing the effects of age or AD pathologies on the brain. This article is part of the Special Issue on "Microglia".
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Affiliation(s)
- Sarah E Heuer
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA; Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Erik B Bloss
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA; Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, 02111, USA; Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, 04469, USA.
| | - Gareth R Howell
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA; Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, 02111, USA; Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, 04469, USA.
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3
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Regele-Blasco E, Palmer LM. The plasticity of pyramidal neurons in the behaving brain. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230231. [PMID: 38853566 DOI: 10.1098/rstb.2023.0231] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 04/23/2024] [Indexed: 06/11/2024] Open
Abstract
Neurons are plastic. That is, they change their activity according to different behavioural conditions. This endows pyramidal neurons with an incredible computational power for the integration and processing of synaptic inputs. Plasticity can be investigated at different levels of investigation within a single neuron, from spines to dendrites, to synaptic input. Although most of our knowledge stems from the in vitro brain slice preparation, plasticity plays a vital role during behaviour by providing a flexible substrate for the execution of appropriate actions in our ever-changing environment. Owing to advances in recording techniques, the plasticity of neurons and the neural networks in which they are embedded is now beginning to be realized in the in vivo intact brain. This review focuses on the structural and functional synaptic plasticity of pyramidal neurons, with a specific focus on the latest developments from in vivo studies. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Elena Regele-Blasco
- The Florey Institute of Neuroscience and Mental Health, The Florey Department of Neuroscience and Mental Health, University of Melbourne , Victoria 3052, Australia
| | - Lucy M Palmer
- The Florey Institute of Neuroscience and Mental Health, The Florey Department of Neuroscience and Mental Health, University of Melbourne , Victoria 3052, Australia
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Nowacka A, Getz AM, Bessa-Neto D, Choquet D. Activity-dependent diffusion trapping of AMPA receptors as a key step for expression of early LTP. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230220. [PMID: 38853553 DOI: 10.1098/rstb.2023.0220] [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: 02/24/2024] [Accepted: 04/11/2024] [Indexed: 06/11/2024] Open
Abstract
This review focuses on the activity-dependent diffusion trapping of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) as a crucial mechanism for the expression of early long-term potentiation (LTP), a process central to learning and memory. Despite decades of research, the precise mechanisms by which LTP induction leads to an increase in AMPAR responses at synapses have been elusive. We review the different hypotheses that have been put forward to explain the increased AMPAR responsiveness during LTP. We discuss the dynamic nature of AMPAR complexes, including their constant turnover and activity-dependent modifications that affect their synaptic accumulation. We highlight a hypothesis suggesting that AMPARs are diffusively trapped at synapses through activity-dependent interactions with protein-based binding slots in the post-synaptic density (PSD), offering a potential explanation for the increased synaptic strength during LTP. Furthermore, we outline the challenges still to be addressed before we fully understand the functional roles and molecular mechanisms of AMPAR dynamic nanoscale organization in LTP. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Agata Nowacka
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
| | - Angela M Getz
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4 , Bordeaux F-33000, France
| | - Diogo Bessa-Neto
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4 , Bordeaux F-33000, France
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Li XY, Zhang SY, Hong YZ, Chen ZG, Long Y, Yuan DH, Zhao JJ, Tang SS, Wang H, Hong H. TGR5-mediated lateral hypothalamus-dCA3-dorsolateral septum circuit regulates depressive-like behavior in male mice. Neuron 2024; 112:1795-1814.e10. [PMID: 38518778 DOI: 10.1016/j.neuron.2024.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 01/30/2024] [Accepted: 02/28/2024] [Indexed: 03/24/2024]
Abstract
Although bile acids play a notable role in depression, the pathological significance of the bile acid TGR5 membrane-type receptor in this disorder remains elusive. Using depression models of chronic social defeat stress and chronic restraint stress in male mice, we found that TGR5 in the lateral hypothalamic area (LHA) predominantly decreased in GABAergic neurons, the excitability of which increased in depressive-like mice. Upregulation of TGR5 or inhibition of GABAergic excitability in LHA markedly alleviated depressive-like behavior, whereas down-regulation of TGR5 or enhancement of GABAergic excitability facilitated stress-induced depressive-like behavior. TGR5 also bidirectionally regulated excitability of LHA GABAergic neurons via extracellular regulated protein kinases-dependent Kv4.2 channels. Notably, LHA GABAergic neurons specifically innervated dorsal CA3 (dCA3) CaMKIIα neurons for mediation of depressive-like behavior. LHA GABAergic TGR5 exerted antidepressant-like effects by disinhibiting dCA3 CaMKIIα neurons projecting to the dorsolateral septum (DLS). These findings advance our understanding of TGR5 and the LHAGABA→dCA3CaMKIIα→DLSGABA circuit for the development of potential therapeutic strategies in depression.
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Affiliation(s)
- Xu-Yi Li
- College of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Shi-Ya Zhang
- College of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yi-Zhou Hong
- Research Center of Biostatistics and Computational Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Zhi-Gang Chen
- College of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yan Long
- College of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Dan-Hua Yuan
- College of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Jia-Jia Zhao
- College of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Su-Su Tang
- College of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
| | - Hao Wang
- Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine/Nanhu Brain-Computer Interface Institute, Hangzhou 310013, China.
| | - Hao Hong
- College of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
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Sun Y, Zhang H, Liu R, Wang Y, Zhang X, Huang R, Zhu B, Wu H. Zexieyin formula alleviates Alzheimer's disease via post-synaptic CaMKII modulating AMPA receptor: Involved in promoting neurogenesis to strengthen synaptic plasticity in mice hippocampus. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 131:155802. [PMID: 38852473 DOI: 10.1016/j.phymed.2024.155802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 05/18/2024] [Accepted: 06/02/2024] [Indexed: 06/11/2024]
Abstract
BACKGROUND Alzheimer's disease (AD) is a serious neurodegenerative disease and brings a serious burden to society and families. Due to lack of effective drugs for the treatment of AD, it's urgent to develop new and effective drug for the treatment of AD. PURPOSE The study aimed to investigate the potential of Zexieyin formula (ZXYF), a Chinese medicine formula, for the treatment of AD and its potential mechanism of action. METHODS We used chronic scopolamine (SCOP) induction mice model and APP/PS1 mice to reveal and confirm ZXYF for the treatment of AD with donepezil (DON) as a positive reference. The learning and memory function were detected by morris water maze test (MWM) and y-maze test. Moreover, western blot and immunofluorescence were used to detect the molecular mechanism of ZXYF for the alleviation of AD in hippocampus. Lastly, pharmacological technology was applied to evaluate AMPA receptor involved in the role of ZXYF in the treatment of AD. RESULTS The results showed that ZXYF could improve memory and learning deficits both in two AD models including scopolamine (SCOP)-induced mice model and APP/PS1mice. Moreover, ZXYF or not DON increased expressions of BrdU/DCX and Ki67 positive cells in dentate gyrus (DG), up-regulated the levels of AMPA subunit type (GluA1) and PKA in hippocampus in SCOP-induced mice model, although ZXYF and DON activated CaMKII, CaMKII-phosphorylation, CREB, CREB-phosphorylation and PSD95 in hippocampus in SCOP-induced mice model. ZXYF also activated CaMKII, CaMKII-phosphorylation and GluA1 in HT22 cells. Furthermore, transient inhibiting AMPA receptor was capable of blocking the effects of ZXYF to treat AD in MWM and suppressing the number of BrdU/DCX positive cells increased by ZXYF in DG in SCOP-induced mice model, but had no effect on the alteration of Ki67 positive cells. CONCLUSION ZXYF had the therapeutic effects on AD-treatment, which activated CaMKII to promote AMPA receptor (GluA1) and subsequently up-regulated PKA/CREB signaling to facilitate neurogenesis to achieve enhanced postsynaptic protein.
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Affiliation(s)
- Yan Sun
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing 210023, PR China
| | - Hailou Zhang
- Interdisciplinary Institute for Personalized Medicine in Brain Disorders, Jinan University, Guangzhou 510632, PR China.
| | - Ruiyi Liu
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing 210023, PR China; Interdisciplinary Institute for Personalized Medicine in Brain Disorders, Jinan University, Guangzhou 510632, PR China
| | - Yanqing Wang
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing 210023, PR China
| | - Xiangrui Zhang
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing 210023, PR China
| | - Rumin Huang
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing 210023, PR China
| | - Boran Zhu
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing 210023, PR China.
| | - Haoxin Wu
- Key Laboratory of Integrative Biomedicine for Brain Diseases, School of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; National Famous Chinese Medicine Expert Inheritance Studio (Meng Jingchun), Nanjing University of Chinese Medicine, School of Chinese Medicine, Nanjing 210023, PR China.
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Ju Y, Baek DH, Choi GE, Jang A. Exploring microRNA patterns as biomarkers of FOLFOX chemotherapy-induced peripheral neuropathy in patients with colorectal cancer. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167209. [PMID: 38701955 DOI: 10.1016/j.bbadis.2024.167209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 04/11/2024] [Accepted: 04/25/2024] [Indexed: 05/06/2024]
Abstract
FOLFOX is a combination of chemotherapeutic agents (5-fluorouracil, leucovorin, and oxaliplatin) and is used to treat advanced colorectal cancer (CRC) but induces various side effects. Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most critical side effects that compromise the quality of life of patients with CRC undergoing FOLFOX chemotherapy. This study aimed to evaluate circulating miRNA, cortisol and catecholamine as potential biomarkers that can predict FOLFOX-CIPN symptoms. High-throughput microRNA (miRNA) sequencing was performed on the RNA circulating in the plasma of eight patients with CRC who underwent FOLFOX chemotherapy. miRNA expression profiles were evaluated according to two groups: those who underwent ≤3 cycles and those who underwent ≥6 cycles of FOLFOX chemotherapy. The identified miRNAs were validated in 27 patients with CRC who underwent FOLFOX chemotherapy using quantitative reverse transcription polymerase chain reaction. Target genes were predicted using bioinformatics and functional analyses. Cortisol and catecholamine concentrations in peripheral plasma were measured using an enzyme-linked immunosorbent assay. miR-3184-5p was differentially expressed when miRNA expression was compared between the groups that underwent ≤3 and ≥6 cycles of FOLFOX chemotherapy. Cortisol levels were significantly higher in the group that underwent ≥6 cycles of FOLFOX chemotherapy than in the group that underwent ≤3 cycles. This study suggests that miR-3184-5p may be a potential marker for predicting CIPN.
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Affiliation(s)
- Yeongdon Ju
- Department of Biomedical Laboratory Science, Gimcheon University, Gimcheon 39528, Republic of Korea; Department of Clinical Laboratory Science, College of Health Sciences, Catholic University of Pusan, Busan 46252, Republic of Korea
| | - Dong Hoon Baek
- Department of Internal Medicine, Pusan National University College of Medicine, Yangsan 50612, Republic of Korea; Biomedical Research Institute, Pusan National University Hospital, Busan 49241, Republic of Korea
| | - Go-Eun Choi
- Department of Clinical Laboratory Science, College of Health Sciences, Catholic University of Pusan, Busan 46252, Republic of Korea.
| | - Aelee Jang
- Department of Nursing, University of Ulsan, Ulsan 44610, Republic of Korea.
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Abstract
Neuropathic pain is a debilitating form of pain arising from injury or disease of the nervous system that affects millions of people worldwide. Despite its prevalence, the underlying mechanisms of neuropathic pain are still not fully understood. Dendritic spines are small protrusions on the surface of neurons that play an important role in synaptic transmission. Recent studies have shown that dendritic spines reorganize in the superficial and deeper laminae of the spinal cord dorsal horn with the development of neuropathic pain in multiple models of disease or injury. Given the importance of dendritic spines in synaptic transmission, it is possible that studying dendritic spines could lead to new therapeutic approaches for managing intractable pain. In this review article, we highlight the emergent role of dendritic spines in neuropathic pain, as well as discuss the potential for studying dendritic spines for the development of new therapeutics.
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Affiliation(s)
- Curtis A Benson
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Jared F King
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Marike L Reimer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Sierra D Kauer
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Andrew M Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA
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Linsley JW, Reisine T, Finkbeiner S. Three dimensional (3D) and four dimensional (4D) live imaging to study mechanisms of progressive neurodegeneration. J Biol Chem 2024:107433. [PMID: 38825007 DOI: 10.1016/j.jbc.2024.107433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 05/20/2024] [Accepted: 05/26/2024] [Indexed: 06/04/2024] Open
Abstract
Neurodegenerative diseases are complex and progressive, posing challenges to their study and understanding. Recent advances in microscopy imaging technologies have enabled the exploration of neurons in three spatial dimensions (3D) over time (4D). When applied to 3D cultures, tissues or animals, these technologies can provide valuable insights into the dynamic and spatial nature of neurodegenerative diseases. This review focuses on the use of imaging techniques and neurodegenerative disease models to study neurodegeneration in 4D. Imaging techniques such as confocal microscopy, two-photon microscopy, miniscope imaging, light sheet microscopy, and robotic microscopy offer powerful tools to visualize and analyze neuronal changes over time in 3D tissue. Application of these technologies to in vitro models of neurodegeneration such as mouse organotypic culture systems and human organoid models provide versatile platforms to study neurodegeneration in a physiologically relevant context. Additionally, use of 4D imaging in vivo, including in mouse and zebrafish models of neurodegenerative diseases, allows for the investigation of early dysfunction and behavioral changes associated with neurodegeneration. We propose that these studies have the power to overcome the limitations of two-dimensional (2D) monolayer neuronal cultures, and pave the way for improved understanding of the dynamics of neurodegenerative diseases and the development of effective therapeutic strategies.
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Affiliation(s)
- Jeremy W Linsley
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA 94158, USA; Operant Biopharma, San Francisco, CA 94158, USA
| | - Terry Reisine
- Independent scientific consultant, Santa Cruz CA, USA
| | - Steven Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA 94158, USA; Operant Biopharma, San Francisco, CA 94158, USA; Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, San Francisco, CA 94158, USA; Departments of Neurology and Physiology, University of California, San Francisco, CA 94158, USA; Neuroscience Graduate Program, University of California, San Francisco, CA 94158, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, CA 94143, USA
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10
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Jabra S, Rietsche M, Muellerleile J, O'Leary A, Slattery DA, Deller T, Fellenz M. Sex- and cycle-dependent changes in spine density and size in hippocampal CA2 neurons. Sci Rep 2024; 14:12252. [PMID: 38806649 PMCID: PMC11133407 DOI: 10.1038/s41598-024-62951-x] [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: 02/27/2024] [Accepted: 05/22/2024] [Indexed: 05/30/2024] Open
Abstract
Sex hormones affect structural and functional plasticity in the rodent hippocampus. However, hormone levels not only differ between males and females, but also fluctuate across the female estrous cycle. While sex- and cycle-dependent differences in dendritic spine density and morphology have been found in the rodent CA1 region, but not in the CA3 or the dentate gyrus, comparable structural data on CA2, i.e. the hippocampal region involved in social recognition memory, is so far lacking. In this study, we, therefore, used wildtype male and female mice in diestrus or proestrus to analyze spines on dendritic segments from identified CA2 neurons. In basal stratum oriens, we found no differences in spine density, but a significant shift towards larger spine head areas in male mice compared to females. Conversely, in apical stratum radiatum diestrus females had a significantly higher spine density, and females in either cycle stage had a significant shift towards larger spine head areas as compared to males, with diestrus females showing the larger shift. Our results provide further evidence for the sexual dimorphism of hippocampal area CA2, and underscore the importance of considering not only the sex, but also the stage of the estrous cycle when interpreting morphological data.
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Affiliation(s)
- Sharif Jabra
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Michael Rietsche
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Julia Muellerleile
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Aet O'Leary
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University Frankfurt, University Hospital, Heinrich-Hoffmann-Straße 10, 60528, Frankfurt am Main, Germany
| | - David A Slattery
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University Frankfurt, University Hospital, Heinrich-Hoffmann-Straße 10, 60528, Frankfurt am Main, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Meike Fellenz
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany.
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Flores JC, Zito K. A synapse-specific refractory period for plasticity at individual dendritic spines. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595787. [PMID: 38826343 PMCID: PMC11142223 DOI: 10.1101/2024.05.24.595787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
How newly formed memories are preserved while brain plasticity is ongoing has been a source of debate. One idea is that synapses which experienced recent plasticity become resistant to further plasticity, a type of metaplasticity often referred to as saturation. Here, we probe the local dendritic mechanisms that limit plasticity at recently potentiated synapses. We show that recently potentiated individual synapses exhibit a synapse-specific refractory period for further potentiation. We further found that the refractory period is associated with reduced postsynaptic CaMKII signaling; however, stronger synaptic activation only partially restored the ability for further plasticity. Importantly, the refractory period is released after one hour, a timing that coincides with the enrichment of several postsynaptic proteins to pre-plasticity levels. Notably, increasing the level of the postsynaptic scaffolding protein, PSD95, but not of PSD93, overcomes the refractory period. Our results support a model in which potentiation at a single synapse is sufficient to initiate a synapse-specific refractory period that persists until key postsynaptic proteins regain their steady-state synaptic levels.
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Affiliation(s)
- Juan C. Flores
- Center for Neuroscience, University of California, Davis, CA 95618
| | - Karen Zito
- Center for Neuroscience, University of California, Davis, CA 95618
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12
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Chen S, Lu H, Cheng C, Ye Z, Hua T. Rapidly repeated visual stimulation induces long-term potentiation of VEPs and increased content of membrane AMPA and NMDA receptors in the V1 cortex of cats. Front Neurosci 2024; 18:1386801. [PMID: 38831757 PMCID: PMC11144871 DOI: 10.3389/fnins.2024.1386801] [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: 02/16/2024] [Accepted: 04/25/2024] [Indexed: 06/05/2024] Open
Abstract
Studies report that rapidly repeated sensory stimulation can evoke LTP-like improvement of neural response in the sensory cortex. Whether this neural response potentiation is similar to the classic LTP induced by presynaptic electrical stimulation remains unclear. This study examined the effects of repeated high-frequency (9 Hz) versus low-frequency (1 Hz) visual stimulation on visually-evoked field potentials (VEPs) and the membrane protein content of AMPA / NMDA receptors in the primary visual cortex (V1) of cats. The results showed that repeated high-frequency visual stimulation (HFS) caused a long-term improvement in peak-to-peak amplitude of V1-cortical VEPs in response to visual stimuli at HFS-stimulated orientation (SO: 90°) and non-stimulated orientation (NSO: 180°), but the effect exhibited variations depending on stimulus orientation: the amplitude increase of VEPs in response to visual stimuli at SO was larger, reached a maximum earlier and lasted longer than at NSO. By contrast, repeated low-frequency visual stimulation (LFS) had not significantly affected the amplitude of V1-cortical VEPs in response to visual stimuli at both SO and NSO. Furthermore, the membrane protein content of the key subunit GluA1 of AMPA receptors and main subunit NR1 of AMPA receptors in V1 cortex was significantly increased after HFS but not LFS when compared with that of control cats. Taken together, these results indicate that HFS can induce LTP-like improvement of VEPs and an increase in membrane protein of AMPA and NMDA receptors in the V1 cortex of cats, which is similar to but less specific to stimulus orientation than the classic LTP.
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Affiliation(s)
| | | | | | | | - Tianmiao Hua
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
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13
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Kvello P. Mapping lower secondary school students' conceptions of three aspects critical for understanding the nervous system. PLoS One 2024; 19:e0301090. [PMID: 38709767 PMCID: PMC11073672 DOI: 10.1371/journal.pone.0301090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/09/2024] [Indexed: 05/08/2024] Open
Abstract
Understanding the nervous system is an important but perhaps ambitious goal, particularly for students in lower secondary education. It is important because of its' direct role in both mental and physical health, and it is ambitious because instruction focuses on the human nervous system, which is extremely complex, and subject to numerous misconceptions. Despite its' complexity, the science curricula, both nationally and internationally, emphasize an understanding of the system, and not just knowledge of isolated facts. But what does it mean to understand this system, and what content knowledge is critical for understanding it? Unfortunately, the curricula are usually too general to answer these questions, therefore other sources of information are needed. Using the science literature, the present study defines the system level of the nervous system and proposes three basic aspects necessary to understand it: 1) neural circuit architecture, 2) synaptic action, and 3) nerve signal origin. With this background, the aim of the present study is to identify lower secondary school students' conceptions of these three aspects, and to determine how they impact students' understanding of the system. To reach this aim, the study used a questionary which allowed for a mixed method design, and the results show that many students have an immediate conception of the brain as the origin of nerve signals. In addition, many students hold the alternative conceptions that 1) synaptic action is exclusively excitatory, and that 2) neural circuits consists of neurons connected in a chain, one single neuron after another. These alternative conceptions prevent students from understanding the system. Implications for instruction are discussed in the context of conceptual learning theories, and teaching strategies are proposed. Since similar curricula goals and textbook content exist in several countries, the present results may be representative across nations.
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Affiliation(s)
- Pål Kvello
- Department of Teacher Education, Norwegian University of Science and Technology, Trondheim, Norway
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14
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Stockwell I, Watson JF, Greger IH. Tuning synaptic strength by regulation of AMPA glutamate receptor localization. Bioessays 2024:e2400006. [PMID: 38693811 DOI: 10.1002/bies.202400006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
Long-term potentiation (LTP) of excitatory synapses is a leading model to explain the concept of information storage in the brain. Multiple mechanisms contribute to LTP, but central amongst them is an increased sensitivity of the postsynaptic membrane to neurotransmitter release. This sensitivity is predominantly determined by the abundance and localization of AMPA-type glutamate receptors (AMPARs). A combination of AMPAR structural data, super-resolution imaging of excitatory synapses, and an abundance of electrophysiological studies are providing an ever-clearer picture of how AMPARs are recruited and organized at synaptic junctions. Here, we review the latest insights into this process, and discuss how both cytoplasmic and extracellular receptor elements cooperate to tune the AMPAR response at the hippocampal CA1 synapse.
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Affiliation(s)
- Imogen Stockwell
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Jake F Watson
- Institute of Science and Technology, Technology (IST) Austria, Klosterneuburg, Austria
| | - Ingo H Greger
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
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15
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Cao Y, Liu P, Bian H, Jin S, Liu J, Yu N, Cui H, Sun F, Qian X, Qiu W, Ma C. Reduced neurogenesis in human hippocampus with Alzheimer's disease. Brain Pathol 2024; 34:e13225. [PMID: 38012054 PMCID: PMC11007046 DOI: 10.1111/bpa.13225] [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: 06/14/2023] [Accepted: 11/06/2023] [Indexed: 11/29/2023] Open
Abstract
Adult hippocampal neurogenesis (AHN), essential for the plasticity of hippocampal structure and function, may be disrupted in Alzheimer's disease (AD). However, the relationship between the changes in AHN and AD-related pathology in humans remains uncertain. By utilizing advanced immunostaining techniques, we could identify multiple biomarkers representing different stages of AHN in postmortem human hippocampal tissue that exhibited various AD-related neuropathological changes. In this study, we observed a significant presence of neurogenic cells in the hippocampus's dentate gyrus (DG) region in 30 individuals, including 14 individuals diagnosed with AD-related neuropathological changes and the remaining 16 individuals without any neurological diseases. Further investigation revealed that patients with AD exhibited pronounced astrogliosis and reduced neurogenesis. Specifically, the number of neuroblasts, immature and early mature granule cells decreased significantly as AD advanced. Although the number of neural stem cells (NSCs) remained unchanged in AD patients compared with mentally healthy individuals, they tended to be more quiescent state regulated by Notch and bone morphogenetic protein (BMP) signaling pathways. These abnormalities were strongly associated with the neuropathological alterations in AD patients. These research findings provide potential insights into the underlying mechanisms that underpin the pathogenesis of AD.
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Affiliation(s)
- Yan Cao
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Pan Liu
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
- Department of Radiation and Medical Oncology, Zhongnan HospitalWuhan UniversityWuhanChina
| | - Hongfei Bian
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Sixuan Jin
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Jiaqi Liu
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Ning Yu
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Huan Cui
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Fengrun Sun
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Xiaojing Qian
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Wenying Qiu
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
| | - Chao Ma
- National Human Brain Bank for Development and Function, Department of Human Anatomy, Histology and Embryology, Neuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical CollegeBeijingChina
- Chinese Institute for Brain ResearchBeijingChina
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16
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Lazarov O, Gupta M, Kumar P, Morrissey Z, Phan T. Memory circuits in dementia: The engram, hippocampal neurogenesis and Alzheimer's disease. Prog Neurobiol 2024; 236:102601. [PMID: 38570083 DOI: 10.1016/j.pneurobio.2024.102601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/05/2024]
Abstract
Here, we provide an in-depth consideration of our current understanding of engrams, spanning from molecular to network levels, and hippocampal neurogenesis, in health and Alzheimer's disease (AD). This review highlights novel findings in these emerging research fields and future research directions for novel therapeutic avenues for memory failure in dementia. Engrams, memory in AD, and hippocampal neurogenesis have each been extensively studied. The integration of these topics, however, has been relatively less deliberated, and is the focus of this review. We primarily focus on the dentate gyrus (DG) of the hippocampus, which is a key area of episodic memory formation. Episodic memory is significantly impaired in AD, and is also the site of adult hippocampal neurogenesis. Advancements in technology, especially opto- and chemogenetics, have made sophisticated manipulations of engram cells possible. Furthermore, innovative methods have emerged for monitoring neurons, even specific neuronal populations, in vivo while animals engage in tasks, such as calcium imaging. In vivo calcium imaging contributes to a more comprehensive understanding of engram cells. Critically, studies of the engram in the DG using these technologies have shown the important contribution of hippocampal neurogenesis for memory in both health and AD. Together, the discussion of these topics provides a holistic perspective that motivates questions for future research.
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Affiliation(s)
- Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Muskan Gupta
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Pavan Kumar
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Zachery Morrissey
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Trongha Phan
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
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17
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Lopez-Ortega E, Choi JY, Hong I, Roth RH, Cudmore RH, Huganir RL. Stimulus-dependent synaptic plasticity underlies neuronal circuitry refinement in the mouse primary visual cortex. Cell Rep 2024; 43:113966. [PMID: 38507408 DOI: 10.1016/j.celrep.2024.113966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 12/26/2023] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
Perceptual learning improves our ability to interpret sensory stimuli present in our environment through experience. Despite its importance, the underlying mechanisms that enable perceptual learning in our sensory cortices are still not fully understood. In this study, we used in vivo two-photon imaging to investigate the functional and structural changes induced by visual stimulation in the mouse primary visual cortex (V1). Our results demonstrate that repeated stimulation leads to a refinement of V1 circuitry by decreasing the number of responsive neurons while potentiating their response. At the synaptic level, we observe a reduction in the number of dendritic spines and an overall increase in spine AMPA receptor levels in the same subset of neurons. In addition, visual stimulation induces synaptic potentiation in neighboring spines within individual dendrites. These findings provide insights into the mechanisms of synaptic plasticity underlying information processing in the neocortex.
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Affiliation(s)
- Elena Lopez-Ortega
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jung Yoon Choi
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ingie Hong
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Richard H Roth
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Robert H Cudmore
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Richard L Huganir
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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18
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Samavat M, Bartol TM, Harris KM, Sejnowski TJ. Synaptic Information Storage Capacity Measured With Information Theory. Neural Comput 2024; 36:781-802. [PMID: 38658027 DOI: 10.1162/neco_a_01659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 01/02/2024] [Indexed: 04/26/2024]
Abstract
Variation in the strength of synapses can be quantified by measuring the anatomical properties of synapses. Quantifying precision of synaptic plasticity is fundamental to understanding information storage and retrieval in neural circuits. Synapses from the same axon onto the same dendrite have a common history of coactivation, making them ideal candidates for determining the precision of synaptic plasticity based on the similarity of their physical dimensions. Here, the precision and amount of information stored in synapse dimensions were quantified with Shannon information theory, expanding prior analysis that used signal detection theory (Bartol et al., 2015). The two methods were compared using dendritic spine head volumes in the middle of the stratum radiatum of hippocampal area CA1 as well-defined measures of synaptic strength. Information theory delineated the number of distinguishable synaptic strengths based on nonoverlapping bins of dendritic spine head volumes. Shannon entropy was applied to measure synaptic information storage capacity (SISC) and resulted in a lower bound of 4.1 bits and upper bound of 4.59 bits of information based on 24 distinguishable sizes. We further compared the distribution of distinguishable sizes and a uniform distribution using Kullback-Leibler divergence and discovered that there was a nearly uniform distribution of spine head volumes across the sizes, suggesting optimal use of the distinguishable values. Thus, SISC provides a new analytical measure that can be generalized to probe synaptic strengths and capacity for plasticity in different brain regions of different species and among animals raised in different conditions or during learning. How brain diseases and disorders affect the precision of synaptic plasticity can also be probed.
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Affiliation(s)
- Mohammad Samavat
- Department of Electrical and Computer Engineering, Jacobs School of Engineering, University of California, San Diego
- Computational Neurobiology Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037, U.S.A.
| | - Thomas M Bartol
- Computational Neurobiology Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037, U.S.A.
| | - Kristen M Harris
- Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX 78712, U.S.A.
| | - Terrence J Sejnowski
- Computational Neurobiology Laboratory, Salk Institute for Biological Sciences, La Jolla, CA 92037, U.S.A
- Department of Neurobiology, University of California, San Diego, La Jolla, CA 92093, U.S.A.
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19
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Lee M, Moon HC, Jeong H, Kim DW, Park HY, Shin Y. Optogenetic control of mRNA condensation reveals an intimate link between condensate material properties and functions. Nat Commun 2024; 15:3216. [PMID: 38622120 PMCID: PMC11018775 DOI: 10.1038/s41467-024-47442-x] [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: 02/16/2023] [Accepted: 03/25/2024] [Indexed: 04/17/2024] Open
Abstract
Biomolecular condensates, often assembled through phase transition mechanisms, play key roles in organizing diverse cellular activities. The material properties of condensates, ranging from liquid droplets to solid-like glasses or gels, are key features impacting the way resident components associate with one another. However, it remains unclear whether and how different material properties would influence specific cellular functions of condensates. Here, we combine optogenetic control of phase separation with single-molecule mRNA imaging to study relations between phase behaviors and functional performance of condensates. Using light-activated condensation, we show that sequestering target mRNAs into condensates causes translation inhibition. Orthogonal mRNA imaging reveals highly transient nature of interactions between individual mRNAs and condensates. Tuning condensate composition and material property towards more solid-like states leads to stronger translational repression, concomitant with a decrease in molecular mobility. We further demonstrate that β-actin mRNA sequestration in neurons suppresses spine enlargement during chemically induced long-term potentiation. Our work highlights how the material properties of condensates can modulate functions, a mechanism that may play a role in fine-tuning the output of condensate-driven cellular activities.
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Affiliation(s)
- Min Lee
- Interdisciplinary Program in Bioengineering, Seoul National University, Seoul, Korea
| | - Hyungseok C Moon
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea
| | - Hyeonjeong Jeong
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, USA
| | - Dong Wook Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea
| | - Hye Yoon Park
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea.
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, USA.
| | - Yongdae Shin
- Interdisciplinary Program in Bioengineering, Seoul National University, Seoul, Korea.
- Department of Mechanical Engineering, Seoul National University, Seoul, Korea.
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20
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Pannoni KE, Fischer QS, Tarannum R, Cawley ML, Alsalman MM, Acosta N, Ezigbo C, Gil DV, Campbell LA, Farris S. MCU-enriched dendritic mitochondria regulate plasticity in distinct hippocampal circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.10.566606. [PMID: 37986798 PMCID: PMC10659405 DOI: 10.1101/2023.11.10.566606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Mitochondria are dynamic organelles that are morphologically and functionally diverse across cell types and subcellular compartments in order to meet unique energy demands. Mitochondrial dysfunction has been implicated in a wide variety of neurological disorders, including psychiatric disorders like schizophrenia and bipolar disorder. Despite it being well known that mitochondria are essential for synaptic transmission and synaptic plasticity, the mechanisms regulating mitochondria in support of normal synapse function are incompletely understood. The mitochondrial calcium uniporter (MCU) regulates calcium entry into the mitochondria, which in turn regulates the bioenergetics and distribution of mitochondria to active synapses. Evidence suggests that calcium influx via MCU couples neuronal activity to mitochondrial metabolism and ATP production, which would allow neurons to rapidly adapt to changing energy demands. Intriguingly, MCU is uniquely enriched in hippocampal CA2 distal dendrites relative to neighboring hippocampal CA1 or CA3 distal dendrites, however, the functional significance of this enrichment is not clear. Synapses from the entorhinal cortex layer II (ECII) onto CA2 distal dendrites readily express long term potentiation (LTP), unlike the LTP-resistant synapses from CA3 onto CA2 proximal dendrites, but the mechanisms underlying these different plasticity profiles are unknown. We hypothesized that enrichment of MCU near ECII-CA2 synapses promotes LTP in an otherwise plasticity-restricted cell type. Using a CA2-specific MCU knockout (cKO) mouse, we found that MCU is required for LTP at distal dendrite synapses but does not affect the lack of LTP at proximal dendrite synapses. Loss of LTP at ECII-CA2 synapses correlated with a trend for decreased spine density in CA2 distal dendrites of cKO mice compared to control (CTL) mice, which was predominantly seen in immature spines. Moreover, mitochondria were significantly smaller and more numerous across all dendritic layers of CA2 in cKO mice compared to CTL mice, suggesting an overall increase in mitochondrial fragmentation. Fragmented mitochondria might have functional changes, such as altered ATP production, that might explain a deficit in synaptic plasticity. Collectively, our data reveal that MCU regulates layer-specific forms of plasticity in CA2 dendrites, potentially by maintaining proper mitochondria morphology and distribution within dendrites. Differences in MCU expression across different cell types and circuits might be a general mechanism to tune the sensitivity of mitochondria to cytoplasmic calcium levels to power synaptic plasticity.
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Affiliation(s)
- Katy E. Pannoni
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Quentin S. Fischer
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Renesa Tarannum
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia
| | - Mikel L. Cawley
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia
| | - Mayd M. Alsalman
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Nicole Acosta
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Chisom Ezigbo
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Daniela V. Gil
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Logan A. Campbell
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Shannon Farris
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia
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21
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Guo Z, Long T, Yao J, Li Y, Xiao L, Chen M. Potential antidepressant effects of Traditional Chinese botanical drug formula Chaihu-Shugan-San and its active ingredients. Front Pharmacol 2024; 15:1337876. [PMID: 38628641 PMCID: PMC11019007 DOI: 10.3389/fphar.2024.1337876] [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: 11/13/2023] [Accepted: 03/13/2024] [Indexed: 04/19/2024] Open
Abstract
Background: Depression is a severe mental disorder that poses a significant threat to both the physical and mental wellbeing of individuals. Currently, there are various methods for treating depression, including traditional Chinese herbal formulations like Chaihu-Shugan-San (CSS), which have shown effective antidepressant effects in both clinical and animal research. Objective: This review aims to provide a comprehensive synthesis of evidence related to CSS, considering both preclinical and clinical studies, to uncover its potential multi-level, multi-pathway, and multi-target mechanisms for treating depression and identify its active ingredients. Methods: A thorough search was conducted in electronic databases, including PubMed, MEDLINE, Web of Science, Google Scholar, CNKI, and Wanfang, using keywords such as "Chaihu Shugan" and "depression" to retrieve relevant literature on CSS and its active ingredients. The review process adhered to the PRISMA guidelines. Results: This review consolidates the mechanisms underlying antidepressant effects of CSS and its active ingredients. It emphasizes its involvement in the regulation of monoaminergic neurotransmitter systems, synaptic plasticity, and the hypothalamic-pituitary-adrenal axis, among other aspects. Conclusion: CSS exerts a pivotal role in treating depression through various pathways, including the monoaminergic neurotransmitter system, the hypothalamic-pituitary-adrenal axis, synaptic plasticity, inflammation, brain-derived neurotrophic factor levels, and the brain-gut axis. This review facilitates a comprehensive understanding of the current state of CSS research, fostering an in-depth exploration of the etiological mechanisms of depression and the potential discovery of novel antidepressant drugs.
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Affiliation(s)
- Ziyi Guo
- Faculty of Chinese Medicine and State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, Macao SAR, China
| | - Tianjian Long
- Henan University of Chinese Medicine, Zhengzhou, China
| | - Jianping Yao
- Henan University of Chinese Medicine, Zhengzhou, China
| | - Yamin Li
- Henan University of Chinese Medicine, Zhengzhou, China
| | - Lu Xiao
- Zunyi Medical University, Zhuhai, China
| | - Min Chen
- Faculty of Chinese Medicine and State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, Macao SAR, China
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22
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Park H, Kaang BK. Memory allocation at the neuronal and synaptic levels. BMB Rep 2024; 57:176-181. [PMID: 37964638 PMCID: PMC11058361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/05/2023] [Accepted: 11/10/2023] [Indexed: 11/16/2023] Open
Abstract
Memory allocation, which determines where memories are stored in specific neurons or synapses, has consistently been demonstrated to occur via specific mechanisms. Neuronal allocation studies have focused on the activated population of neurons and have shown that increased excitability via cAMP response element-binding protein (CREB) induces a bias toward memoryencoding neurons. Synaptic allocation suggests that synaptic tagging enables memory to be mediated through different synaptic strengthening mechanisms, even within a single neuron. In this review, we summarize the fundamental concepts of memory allocation at the neuronal and synaptic levels and discuss their potential interrelationships. [BMB Reports 2024; 57(4): 176-181].
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Affiliation(s)
- HyoJin Park
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science (IBS), Daejeon 34126, Korea
- Department of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Bong-Kiun Kaang
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science (IBS), Daejeon 34126, Korea
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23
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Espadas I, Wingfield JL, Nakahata Y, Chanda K, Grinman E, Ghosh I, Bauer KE, Raveendra B, Kiebler MA, Yasuda R, Rangaraju V, Puthanveettil S. Synaptically-targeted long non-coding RNA SLAMR promotes structural plasticity by increasing translation and CaMKII activity. Nat Commun 2024; 15:2694. [PMID: 38538603 PMCID: PMC10973417 DOI: 10.1038/s41467-024-46972-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
Long noncoding RNAs (lncRNAs) play crucial roles in maintaining cell homeostasis and function. However, it remains largely unknown whether and how neuronal activity impacts the transcriptional regulation of lncRNAs, or if this leads to synapse-related changes and contributes to the formation of long-term memories. Here, we report the identification of a lncRNA, SLAMR, which becomes enriched in CA1-hippocampal neurons upon contextual fear conditioning but not in CA3 neurons. SLAMR is transported along dendrites via the molecular motor KIF5C and is recruited to the synapse upon stimulation. Loss of function of SLAMR reduces dendritic complexity and impairs activity-dependent changes in spine structural plasticity and translation. Gain of function of SLAMR, in contrast, enhances dendritic complexity, spine density, and translation. Analyses of the SLAMR interactome reveal its association with CaMKIIα protein through a 220-nucleotide element also involved in SLAMR transport. A CaMKII reporter reveals a basal reduction in CaMKII activity with SLAMR loss-of-function. Furthermore, the selective loss of SLAMR function in CA1 disrupts the consolidation of fear memory in male mice, without affecting their acquisition, recall, or extinction, or spatial memory. Together, these results provide new molecular and functional insight into activity-dependent changes at the synapse and consolidation of contextual fear.
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Affiliation(s)
- Isabel Espadas
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Jenna L Wingfield
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | | | - Kaushik Chanda
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Eddie Grinman
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Ilika Ghosh
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA
| | - Karl E Bauer
- Biomedical Center, Department for Cell Biology, Ludwig-Maximilians-University of Munich, Medical Faculty, 82152, Planegg-Martinsried, Germany
| | - Bindu Raveendra
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Michael A Kiebler
- Biomedical Center, Department for Cell Biology, Ludwig-Maximilians-University of Munich, Medical Faculty, 82152, Planegg-Martinsried, Germany
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA
| | | | - Sathyanarayanan Puthanveettil
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA.
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24
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Meyers AM, Gnazzo F, Barrera ED, Nabatian T, Chan L, Beeler J. DIETARY REGULATION OF SILENT SYNAPSES IN THE DORSOLATERAL STRIATUM. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.24.586457. [PMID: 38585967 PMCID: PMC10996560 DOI: 10.1101/2024.03.24.586457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Obesity results in circuit adaptations that closely resemble those induced by drugs of abuse. AMPA-lacking 'silent' synapses are critical in circuit generation during early development, but largely disappear by adulthood. Drugs of abuse increase silent synapses during adulthood and may facilitate the reorganization of brain circuits around drug-related experience, facilitating addiction and relapse Whether obesity causes addiction-related synaptic circuit reorganization via alterations in silent synapse expression has not been examined. Using a dietary-induced obesity paradigm, we show that mice that chronically consumed high-fat diet (HFD) exhibit upregulated silent synapses in both direct and indirect pathway medium spiny neurons in the dorsolateral striatum. Both the onset of silent synapses and their re-silencing after HFD withdrawal occur on an extended time scale of weeks rather than days. Our data suggest that HFD-related silent synapses likely arise from AMPA receptor internalization rather than through de novo synaptogenesis of NR2B-containing NMDA receptors. These data demonstrate that chronic consumption of high-fat diet can alter mechanisms of circuit plasticity, likely facilitating neural reorganization analogous to that observed with drugs of abuse.
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Affiliation(s)
- Allison M Meyers
- Department of Psychology, Queens College, City University New York, Flushing, NY, USA
- Psychology Program, The Graduate Center, City University of New York, New York, NY, USA
| | - Federico Gnazzo
- Department of Psychology, Queens College, City University New York, Flushing, NY, USA
| | - Eddy D Barrera
- Department of Psychology, Queens College, City University New York, Flushing, NY, USA
- Biology Program, The Graduate Center, City University of New York, New York NY, USA
| | - Tikva Nabatian
- Cognitive Neuroscience MS program, The Graduate Center, City University of New York NY, USA
| | - Larry Chan
- Department of Psychology, Queens College, City University New York, Flushing, NY, USA
| | - Jeff Beeler
- Department of Psychology, Queens College, City University New York, Flushing, NY, USA
- Psychology Program, The Graduate Center, City University of New York, New York, NY, USA
- Biology Program, The Graduate Center, City University of New York, New York NY, USA
- Cognitive Neuroscience MS program, The Graduate Center, City University of New York NY, USA
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25
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Berry JA, Guhle DC, Davis RL. Active forgetting and neuropsychiatric diseases. Mol Psychiatry 2024:10.1038/s41380-024-02521-9. [PMID: 38532011 DOI: 10.1038/s41380-024-02521-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 03/28/2024]
Abstract
Recent and pioneering animal research has revealed the brain utilizes a variety of molecular, cellular, and network-level mechanisms used to forget memories in a process referred to as "active forgetting". Active forgetting increases behavioral flexibility and removes irrelevant information. Individuals with impaired active forgetting mechanisms can experience intrusive memories, distressing thoughts, and unwanted impulses that occur in neuropsychiatric diseases. The current evidence indicates that active forgetting mechanisms degrade, or mask, molecular and cellular memory traces created in synaptic connections of "engram cells" that are specific for a given memory. Combined molecular genetic/behavioral studies using Drosophila have uncovered a complex system of cellular active-forgetting pathways within engram cells that is regulated by dopamine neurons and involves dopamine-nitric oxide co-transmission and reception, endoplasmic reticulum Ca2+ signaling, and cytoskeletal remodeling machinery regulated by small GTPases. Some of these molecular cellular mechanisms have already been found to be conserved in mammals. Interestingly, some pathways independently regulate forgetting of distinct memory types and temporal phases, suggesting a multi-layering organization of forgetting systems. In mammals, active forgetting also involves modulation of memory trace synaptic strength by altering AMPA receptor trafficking. Furthermore, active-forgetting employs network level mechanisms wherein non-engram neurons, newly born-engram neurons, and glial cells regulate engram synapses in a state and experience dependent manner. Remarkably, there is evidence for potential coordination between the network and cellular level forgetting mechanisms. Finally, subjects with several neuropsychiatric diseases have been tested and shown to be impaired in active forgetting. Insights obtained from research on active forgetting in animal models will continue to enrich our understanding of the brain dysfunctions that occur in neuropsychiatric diseases.
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Affiliation(s)
- Jacob A Berry
- Department of Biological Sciences, University of Alberta, Edmonton, AL, T6G 2E9, Canada.
| | - Dana C Guhle
- Department of Biological Sciences, University of Alberta, Edmonton, AL, T6G 2E9, Canada
| | - Ronald L Davis
- Department of Neuroscience, UF Scripps Institute for Biomedical Innovation & Technology, 130 Scripps Way, Jupiter, FL, 33458, USA.
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26
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Kochan SMV, Malo MC, Jevtic M, Jahn-Kelleter HM, Wani GA, Ndoci K, Pérez-Revuelta L, Gaedke F, Schäffner I, Lie DC, Schauss A, Bergami M. Enhanced mitochondrial fusion during a critical period of synaptic plasticity in adult-born neurons. Neuron 2024:S0896-6273(24)00167-3. [PMID: 38582081 DOI: 10.1016/j.neuron.2024.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 01/25/2024] [Accepted: 03/11/2024] [Indexed: 04/08/2024]
Abstract
Integration of new neurons into adult hippocampal circuits is a process coordinated by local and long-range synaptic inputs. To achieve stable integration and uniquely contribute to hippocampal function, immature neurons are endowed with a critical period of heightened synaptic plasticity, yet it remains unclear which mechanisms sustain this form of plasticity during neuronal maturation. We found that as new neurons enter their critical period, a transient surge in fusion dynamics stabilizes elongated mitochondrial morphologies in dendrites to fuel synaptic plasticity. Conditional ablation of fusion dynamics to prevent mitochondrial elongation selectively impaired spine plasticity and synaptic potentiation, disrupting neuronal competition for stable circuit integration, ultimately leading to decreased survival. Despite profuse mitochondrial fragmentation, manipulation of competition dynamics was sufficient to restore neuronal survival but left neurons poorly responsive to experience at the circuit level. Thus, by enabling synaptic plasticity during the critical period, mitochondrial fusion facilitates circuit remodeling by adult-born neurons.
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Affiliation(s)
- Sandra M V Kochan
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Meret Cepero Malo
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Milica Jevtic
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Hannah M Jahn-Kelleter
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Gulzar A Wani
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Kristiano Ndoci
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Laura Pérez-Revuelta
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Felix Gaedke
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Iris Schäffner
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Dieter Chichung Lie
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Astrid Schauss
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Matteo Bergami
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine, 50931 Cologne, Germany; Institute of Genetics, University of Cologne, Cologne 50674, Germany; University of Cologne, Faculty of Medicine and University Hospital Cologne, 50937 Cologne, Germany.
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27
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Kaufhold D, Maristany de Las Casas E, Ocaña-Fernández MDÁ, Cazala A, Yuan M, Kulik A, Cholvin T, Steup S, Sauer JF, Eyre MD, Elgueta C, Strüber M, Bartos M. Spine plasticity of dentate gyrus parvalbumin-positive interneurons is regulated by experience. Cell Rep 2024; 43:113806. [PMID: 38377001 DOI: 10.1016/j.celrep.2024.113806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 12/21/2023] [Accepted: 01/31/2024] [Indexed: 02/22/2024] Open
Abstract
Experience-driven alterations in neuronal activity are followed by structural-functional modifications allowing cells to adapt to these activity changes. Structural plasticity has been observed for cortical principal cells. However, how GABAergic interneurons respond to experience-dependent network activity changes is not well understood. We show that parvalbumin-expressing interneurons (PVIs) of the dentate gyrus (DG) possess dendritic spines, which undergo behaviorally induced structural dynamics. Glutamatergic inputs at PVI spines evoke signals with high spatial compartmentalization defined by neck length. Mice experiencing novel contexts form more PVI spines with elongated necks and exhibit enhanced network and PVI activity and cFOS expression. Enhanced green fluorescent protein reconstitution across synaptic partner-mediated synapse labeling shows that experience-driven PVI spine growth boosts targeting of PVI spines over shafts by glutamatergic synapses. Our findings propose a role for PVI spine dynamics in regulating PVI excitation by their inputs, which may allow PVIs to dynamically adjust their functional integration in the DG microcircuitry in relation to network computational demands.
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Affiliation(s)
- Dorthe Kaufhold
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | | | | | - Aurore Cazala
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Mei Yuan
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Akos Kulik
- Institute of Physiology II, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Thibault Cholvin
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Stefanie Steup
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Jonas-Frederic Sauer
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Mark D Eyre
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Claudio Elgueta
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Michael Strüber
- Epilepsy Center Frankfurt Rhine-Main, Center of Neurology and Neurosurgery, Goethe University, 60528 Frankfurt am Main, Germany
| | - Marlene Bartos
- Institute of Physiology I, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.
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28
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Hashimoto J, Fujita E, Tanimoto K, Kondo S, Matsumoto-Miyai K. Effects of Cardiac Glycoside Digoxin on Dendritic Spines and Motor Learning Performance in Mice. Neuroscience 2024; 541:77-90. [PMID: 38278474 DOI: 10.1016/j.neuroscience.2024.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 01/17/2024] [Accepted: 01/22/2024] [Indexed: 01/28/2024]
Abstract
Synapse formation following the generation of postsynaptic dendritic spines is essential for motor learning and functional recovery after brain injury. The C-terminal fragment of agrin cleaved by neurotrypsin induces dendritic spine formation in the adult hippocampus. Since the α3 subunit of sodium-potassium ATPase (Na/K ATPase) is a neuronal receptor for agrin in the central nervous system, cardiac glycosides might facilitate dendritic spine formation and subsequent improvements in learning. This study investigated the effects of cardiac glycoside digoxin on dendritic spine turnover and learning performance in mice. Golgi-Cox staining revealed that intraperitoneal injection of digoxin less than its IC50 in the brain significantly increased the density of long spines (≥2 µm) in the cerebral cortex in wild-type mice and neurotrypsin-knockout (NT-KO) mice showing impairment of activity-dependent spine formation. Although the motor learning performance of NT-KO mice was significantly lower than control wild-type mice under the control condition, low doses of digoxin enhanced performance to a similar degree in both strains. In NT-KO mice, lower digoxin doses equivalent to clinical doses also significantly improved motor learning performance. These data suggest that lower doses of digoxin could modify dendritic spine formation or recycling and facilitate motor learning in compensation for the disruption of neurotrypsin-agrin pathway.
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Affiliation(s)
- Junichi Hashimoto
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Erika Fujita
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Keisuke Tanimoto
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Suzuo Kondo
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Kazumasa Matsumoto-Miyai
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan.
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29
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Hedrick NG, Wright WJ, Komiyama T. Local and global predictors of synapse elimination during motor learning. SCIENCE ADVANCES 2024; 10:eadk0540. [PMID: 38489360 PMCID: PMC10942101 DOI: 10.1126/sciadv.adk0540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 02/12/2024] [Indexed: 03/17/2024]
Abstract
During learning, synaptic connections between excitatory neurons in the brain display considerable dynamism, with new connections being added and old connections eliminated. Synapse elimination offers an opportunity to understand the features of synapses that the brain deems dispensable. However, with limited observations of synaptic activity and plasticity in vivo, the features of synapses subjected to elimination remain poorly understood. Here, we examined the functional basis of synapse elimination in the apical dendrites of L2/3 neurons in the primary motor cortex throughout motor learning. We found no evidence that synapse elimination is facilitated by a lack of activity or other local forms of plasticity. Instead, eliminated synapses display asynchronous activity with nearby synapses, suggesting that functional synaptic clustering is a critical component of synapse survival. In addition, eliminated synapses show delayed activity timing with respect to postsynaptic output. Thus, synaptic inputs that fail to be co-active with their neighboring synapses or are mistimed with neuronal output are targeted for elimination.
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Affiliation(s)
- Nathan G. Hedrick
- Department of Neurobiology, University of California San Diego, La Jolla, CA, USA
- Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, USA
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA, USA
| | - William J. Wright
- Department of Neurobiology, University of California San Diego, La Jolla, CA, USA
- Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, USA
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA, USA
| | - Takaki Komiyama
- Department of Neurobiology, University of California San Diego, La Jolla, CA, USA
- Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, USA
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA, USA
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30
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Anjum R, Clarke VRJ, Nagasawa Y, Murakoshi H, Paradis S. Rem2 interacts with CaMKII at synapses and restricts long-term potentiation in hippocampus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.11.584540. [PMID: 38558974 PMCID: PMC10979978 DOI: 10.1101/2024.03.11.584540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Synaptic plasticity, the process whereby neuronal connections are either strengthened or weakened in response to stereotyped forms of stimulation, is widely believed to represent the molecular mechanism that underlies learning and memory. The holoenzyme CaMKII plays a well-established and critical role in the induction of a variety of forms of synaptic plasticity such as long-term potentiation (LTP), long-term depression (LTD) and depotentiation. Previously, we identified the GTPase Rem2 as a potent, endogenous inhibitor of CaMKII. Here, we report that knock out of Rem2 enhances LTP at the Schaffer collateral to CA1 synapse in hippocampus, consistent with an inhibitory action of Rem2 on CaMKII in vivo. Further, re-expression of WT Rem2 rescues the enhanced LTP observed in slices obtained from Rem2 conditional knock out (cKO) mice, while expression of a mutant Rem2 construct that is unable to inhibit CaMKII in vitro fails to rescue increased LTP. In addition, we demonstrate that CaMKII and Rem2 interact in dendritic spines using a 2pFLIM-FRET approach. Taken together, our data lead us to propose that Rem2 serves as a brake on runaway synaptic potentiation via inhibition of CaMKII activity. Further, the enhanced LTP phenotype we observe in Rem2 cKO slices reveals a previously unknown role for Rem2 in the negative regulation of CaMKII function.
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Affiliation(s)
- Rabia Anjum
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454, United States of America
| | - Vernon R J Clarke
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Yutaro Nagasawa
- Department of Physiological Sciences, The Graduate University for Advanced Studies; Hayama, Kanagawa 240-0193, Japan
- Supportive Center for Brain Research, National Institute for Physiological Sciences; Okazaki, Aichi 444-8585, Japan
| | - Hideji Murakoshi
- Department of Physiological Sciences, The Graduate University for Advanced Studies; Hayama, Kanagawa 240-0193, Japan
- Supportive Center for Brain Research, National Institute for Physiological Sciences; Okazaki, Aichi 444-8585, Japan
| | - Suzanne Paradis
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454, United States of America
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31
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Dunton KL, Hedrick NG, Meamardoost S, Ren C, Howe JR, Wang J, Root CM, Gunawan R, Komiyama T, Zhang Y, Hwang EJ. Divergent Learning-Related Transcriptional States of Cortical Glutamatergic Neurons. J Neurosci 2024; 44:e0302232023. [PMID: 38238073 PMCID: PMC10919205 DOI: 10.1523/jneurosci.0302-23.2023] [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: 03/09/2023] [Revised: 09/30/2023] [Accepted: 11/10/2023] [Indexed: 03/08/2024] Open
Abstract
Experience-dependent gene expression reshapes neural circuits, permitting the learning of knowledge and skills. Most learning involves repetitive experiences during which neurons undergo multiple stages of functional and structural plasticity. Currently, the diversity of transcriptional responses underlying dynamic plasticity during repetition-based learning is poorly understood. To close this gap, we analyzed single-nucleus transcriptomes of L2/3 glutamatergic neurons of the primary motor cortex after 3 d motor skill training or home cage control in water-restricted male mice. "Train" and "control" neurons could be discriminated with high accuracy based on expression patterns of many genes, indicating that recent experience leaves a widespread transcriptional signature across L2/3 neurons. These discriminating genes exhibited divergent modes of coregulation, differentiating neurons into discrete clusters of transcriptional states. Several states showed gene expressions associated with activity-dependent plasticity. Some of these states were also prominent in the previously published reference, suggesting that they represent both spontaneous and task-related plasticity events. Markedly, however, two states were unique to our dataset. The first state, further enriched by motor training, showed gene expression suggestive of late-stage plasticity with repeated activation, which is suitable for expected emergent neuronal ensembles that stably retain motor learning. The second state, equally found in both train and control mice, showed elevated levels of metabolic pathways and norepinephrine sensitivity, suggesting a response to common experiences specific to our experimental conditions, such as water restriction or circadian rhythm. Together, we uncovered divergent transcriptional responses across L2/3 neurons, each potentially linked with distinct features of repetition-based motor learning such as plasticity, memory, and motivation.
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Affiliation(s)
- Katie L Dunton
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston 02881, Rhode Island
| | - Nathan G Hedrick
- Department of Neurobiology, Center for Neural Circuits and Behavior, Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla 92093, California
| | - Saber Meamardoost
- Department of Chemical and Biological Engineering, University at Buffalo-SUNY, Buffalo 14260, New York
| | - Chi Ren
- Department of Neurobiology, Center for Neural Circuits and Behavior, Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla 92093, California
| | - James R Howe
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla 92093, California
- Neurosciences Graduate Program, University of California San Diego, La Jolla 92093, California
| | - Jing Wang
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston 02881, Rhode Island
| | - Cory M Root
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla 92093, California
| | - Rudiyanto Gunawan
- Department of Chemical and Biological Engineering, University at Buffalo-SUNY, Buffalo 14260, New York
| | - Takaki Komiyama
- Department of Neurobiology, Center for Neural Circuits and Behavior, Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla 92093, California
| | - Ying Zhang
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston 02881, Rhode Island
| | - Eun Jung Hwang
- Department of Neurobiology, Center for Neural Circuits and Behavior, Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla 92093, California
- Cell Biology and Anatomy, Chicago Medical School, Stanson Toshok Center for Brain Function and Repair, Rosalind Franklin University of Medicine and Science, North Chicago 60064, Illinois
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32
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Bonilla-Quintana M, Rangamani P. Biophysical Modeling of Actin-Mediated Structural Plasticity Reveals Mechanical Adaptation in Dendritic Spines. eNeuro 2024; 11:ENEURO.0497-23.2024. [PMID: 38383589 DOI: 10.1523/eneuro.0497-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/13/2024] [Indexed: 02/23/2024] Open
Abstract
Synaptic plasticity is important for learning and memory formation; it describes the strengthening or weakening of connections between synapses. The postsynaptic part of excitatory synapses resides in dendritic spines, which are small protrusions on the dendrites. One of the key features of synaptic plasticity is its correlation with the size of these spines. A long-lasting synaptic strength increase [long-term potentiation (LTP)] is only possible through the reconfiguration of the actin spine cytoskeleton. Here, we develop an experimentally informed three-dimensional computational model in a moving boundary framework to investigate this reconfiguration. Our model describes the reactions between actin and actin-binding proteins leading to the cytoskeleton remodeling and their effect on the spine membrane shape to examine the spine enlargement upon LTP. Moreover, we find that the incorporation of perisynaptic elements enhances spine enlargement upon LTP, exhibiting the importance of accounting for these elements when studying structural LTP. Our model shows adaptation to repeated stimuli resulting from the interactions between spine proteins and mechanical forces.
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Affiliation(s)
- Mayte Bonilla-Quintana
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093
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33
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Nunes M, Madeira N, Fonseca R. Cdc42 activation is necessary for heterosynaptic cooperation and competition. Mol Cell Neurosci 2024; 129:103921. [PMID: 38428552 DOI: 10.1016/j.mcn.2024.103921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/03/2024] Open
Abstract
Synapses change their weights in response to neuronal activity and in turn, neuronal networks alter their response properties and ultimately allow the brain to store information as memories. As for memories, not all events are maintained over time. Maintenance of synaptic plasticity depends on the interplay between functional changes at synapses and the synthesis of plasticity-related proteins that are involved in stabilizing the initial functional changes. Different forms of synaptic plasticity coexist in time and across the neuronal dendritic area. Thus, homosynaptic plasticity refers to activity-dependent synaptic modifications that are input-specific, whereas heterosynaptic plasticity relates to changes in non-activated synapses. Heterosynaptic forms of plasticity, such as synaptic cooperation and competition allow neurons to integrate events that occur separated by relatively large time windows, up to one hour. Here, we show that activation of Cdc42, a Rho GTPase that regulates actin cytoskeleton dynamics, is necessary for the maintenance of long-term potentiation (LTP) in a time-dependent manner. Inhibiting Cdc42 activation does not alter the time-course of LTP induction and its initial expression but blocks its late maintenance. We show that Cdc42 activation is involved in the phosphorylation of cofilin, a protein involved in modulating actin filaments and that weak and strong synaptic activation leads to similar levels on cofilin phosphorylation, despite different levels of LTP expression. We show that Cdc42 activation is required for synapses to interact by cooperation or competition, supporting the hypothesis that modulation of the actin cytoskeleton provides an activity-dependent and time-restricted permissive state of synapses allowing synaptic plasticity to occur. We found that under competition, the sequence in which synapses are activated determines the degree of LTP destabilization, demonstrating that competition is an active destabilization process. Taken together, we show that modulation of actin cytoskeleton by Cdc42 activation is necessary for the expression of homosynaptic and heterosynaptic forms of plasticity. Determining the temporal and spatial rules that determine whether synapses cooperate or compete will allow us to understand how memories are associated.
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Affiliation(s)
- Mariana Nunes
- Cellular and Systems Neurobiology, NOVA Medical Research, NOVA Medical School, Universidade NOVA de Lisboa, Portugal
| | - Natália Madeira
- Cellular and Systems Neurobiology, NOVA Medical Research, NOVA Medical School, Universidade NOVA de Lisboa, Portugal
| | - Rosalina Fonseca
- Cellular and Systems Neurobiology, NOVA Medical Research, NOVA Medical School, Universidade NOVA de Lisboa, Portugal.
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Ogelman R, Gomez Wulschner LE, Hoelscher VM, Hwang IW, Chang VN, Oh WC. Serotonin modulates excitatory synapse maturation in the developing prefrontal cortex. Nat Commun 2024; 15:1368. [PMID: 38365905 PMCID: PMC10873381 DOI: 10.1038/s41467-024-45734-w] [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: 04/21/2023] [Accepted: 02/02/2024] [Indexed: 02/18/2024] Open
Abstract
Serotonin (5-HT) imbalances in the developing prefrontal cortex (PFC) are linked to long-term behavioral deficits. However, the synaptic mechanisms underlying 5-HT-mediated PFC development are unknown. We found that chemogenetic suppression and enhancement of 5-HT release in the PFC during the first two postnatal weeks decreased and increased the density and strength of excitatory spine synapses, respectively, on prefrontal layer 2/3 pyramidal neurons in mice. 5-HT release on single spines induced structural and functional long-term potentiation (LTP), requiring both 5-HT2A and 5-HT7 receptor signals, in a glutamatergic activity-independent manner. Notably, LTP-inducing 5-HT stimuli increased the long-term survival of newly formed spines ( ≥ 6 h) via 5-HT7 Gαs activation. Chronic treatment of mice with fluoxetine, a selective serotonin-reuptake inhibitor, during the first two weeks, but not the third week of postnatal development, increased the density and strength of excitatory synapses. The effect of fluoxetine on PFC synaptic alterations in vivo was abolished by 5-HT2A and 5-HT7 receptor antagonists. Our data describe a molecular basis of 5-HT-dependent excitatory synaptic plasticity at the level of single spines in the PFC during early postnatal development.
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Affiliation(s)
- Roberto Ogelman
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Luis E Gomez Wulschner
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Victoria M Hoelscher
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - In-Wook Hwang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Victoria N Chang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Won Chan Oh
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA.
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Reyes-Lizaola S, Luna-Zarate U, Tendilla-Beltrán H, Morales-Medina JC, Flores G. Structural and biochemical alterations in dendritic spines as key mechanisms for severe mental illnesses. Prog Neuropsychopharmacol Biol Psychiatry 2024; 129:110876. [PMID: 37863171 DOI: 10.1016/j.pnpbp.2023.110876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/22/2023]
Abstract
Severe mental illnesses (SMI) collectively affect approximately 20% of the global population, as estimated by the World Health Organization (WHO). Despite having diverse etiologies, clinical symptoms, and pharmacotherapies, these diseases share a common pathophysiological characteristic: the misconnection of brain areas involved in reality perception, executive control, and cognition, including the corticolimbic system. Dendritic spines play a crucial role in excitatory neurotransmission within the central nervous system. These small structures exhibit remarkable plasticity, regulated by factors such as neurotransmitter tone, neurotrophic factors, and innate immunity-related molecules, and other mechanisms - all of which are associated with the pathophysiology of SMI. However, studying dendritic spine mechanisms in both healthy and pathological conditions in patients is fraught with technical limitations. This is where animal models related to these diseases become indispensable. They have played a pivotal role in elucidating the significance of dendritic spines in SMI. In this review, the information regarding the potential role of dendritic spines in SMI was summarized, drawing from clinical and animal model reports. Also, the implications of targeting dendritic spine-related molecules for SMI treatment were explored. Specifically, our focus is on major depressive disorder and the neurodevelopmental disorders schizophrenia and autism spectrum disorder. Abundant clinical and basic research has studied the functional and structural plasticity of dendritic spines in these diseases, along with potential pharmacological targets that modulate the dynamics of these structures. These targets may be associated with the clinical efficacy of the pharmacotherapy.
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Affiliation(s)
- Sebastian Reyes-Lizaola
- Departamento de Ciencias de la Salud, Licenciatura en Medicina, Universidad Popular del Estado de Puebla (UPAEP), Puebla, Mexico
| | - Ulises Luna-Zarate
- Departamento de Ciencias de la Salud, Licenciatura en Medicina, Universidad de las Américas Puebla (UDLAP), Puebla, Mexico
| | - Hiram Tendilla-Beltrán
- Laboratorio de Neuropsiquiatría, Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla (BUAP), Puebla, Mexico
| | - Julio César Morales-Medina
- Centro de Investigación en Reproducción Animal, CINVESTAV-Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico
| | - Gonzalo Flores
- Laboratorio de Neuropsiquiatría, Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla (BUAP), Puebla, Mexico.
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Son S, Nagahama K, Lee J, Jung K, Kwak C, Kim J, Noh YW, Kim E, Lee S, Kwon HB, Heo WD. Real-time visualization of structural dynamics of synapses in live cells in vivo. Nat Methods 2024; 21:353-360. [PMID: 38191933 DOI: 10.1038/s41592-023-02122-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 11/01/2023] [Indexed: 01/10/2024]
Abstract
The structural plasticity of synapses is crucial for regulating brain functions. However, currently available methods for studying synapse organization based on split fluorescent proteins (FPs) have been limited in assessing synaptic dynamics in vivo due to the irreversible binding of split FPs. Here, we develop 'SynapShot', a method for visualizing the structural dynamics of intact synapses by combining dimerization-dependent FPs (ddFPs) with engineered synaptic adhesion molecules. SynapShot allows real-time monitoring of reversible and bidirectional changes of synaptic contacts under physiological stimulation. The application of green and red ddFPs in SynapShot enables simultaneous visualization of two distinct populations of synapses. Notably, the red-shifted SynapShot is highly compatible with blue light-based optogenetic techniques, allowing for visualization of synaptic dynamics while precisely controlling specific signaling pathways. Furthermore, we demonstrate that SynapShot enables real-time monitoring of structural changes in synaptic contacts in the mouse brain during both primitive and higher-order behaviors.
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Affiliation(s)
- Seungkyu Son
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Kenichiro Nagahama
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jinsu Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Kanghoon Jung
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Allen Institute for Neural Dynamics, Seattle, WA, USA
| | - Chuljung Kwak
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jihoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Young Woo Noh
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Republic of Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, Republic of Korea
| | - Sangkyu Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, Republic of Korea.
| | - Hyung-Bae Kwon
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA.
| | - Won Do Heo
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
- KAIST Institute for the BioCentury, KAIST, Daejeon, Republic of Korea.
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37
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Feng L, Wang G, Song Q, Feng X, Su J, Ji G, Li M. Proteomics revealed an association between ribosome-associated proteins and amyloid beta deposition in Alzheimer's disease. Metab Brain Dis 2024; 39:263-282. [PMID: 38019374 DOI: 10.1007/s11011-023-01330-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 11/22/2023] [Indexed: 11/30/2023]
Abstract
Most scholars believe that amyloid-beta (Aβ) has the potential to induce apoptosis, stimulate an inflammatory cascade, promote oxidative stress and exacerbate the pathological progression of Alzheimer's disease (AD). Therefore, it is crucial to investigate the deposition of Aβ in AD. At approximately 6 months of age, APP/PS1 double transgenic mice gradually exhibit the development of plaques, as well as spatial and learning impairment. Notably, the hippocampus is specifically affected in the course of AD. Herein, 6-month-old APP/PS1 double transgenic mice were utilized, and the differentially expressed (DE) proteins in the hippocampus were identified and analyzed using 4D label-free quantitative proteomics technology and parallel reaction monitoring (PRM). Compared to wild-type mice, 29 proteins were upregulated and 25 proteins were downregulated in the AD group. Gene Ontology (GO) enrichment analysis of biological processes (BP) indicated that the DE proteins were mainly involved in 'ribosomal large subunit biogenesis'. Molecular function (MF) analysis results were primarily associated with '5.8S rRNA binding' and 'structural constituent of ribosome'. In terms of cellular components (CC), the DE proteins were mainly found in 'polysomal ribosome', 'cytosolic large ribosomal subunit', 'cytosolic ribosome', and 'large ribosomal subunit', among others. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that the results were mainly enriched in the 'Ribosome signaling pathway'. The key target proteins identified were ribosomal protein (Rp)l18, Rpl17, Rpl19, Rpl24, Rpl35, and Rpl6. The PRM verification results were consistent with the findings of the 4D label-free quantitative proteomics analysis. Overall, these findings suggest that Rpl18, Rpl17, Rpl19, Rpl24, Rpl35, and Rpl6 may have potential therapeutic value for the treatment of AD by targeting Aβ.
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Affiliation(s)
- Lina Feng
- Department of Neurology, the Second Affiliated Hospital of Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, Shandong, China
| | - Guojun Wang
- Department of Neurosurgery, The Affiliated Taian City Central Hospital of Qingdao University, Taian, 271000, Shandong, China
| | - Qile Song
- Department of Neurology, the Second Affiliated Hospital of Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, Shandong, China
| | - Xiaotong Feng
- Department of Neurology, the Second Affiliated Hospital of Shandong First Medical University, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, Shandong, China
| | - Jing Su
- Department of Geriatric Cardiovascular, The Affiliated Taian City Central Hospital of Qingdao University, Longtan Road, Taian, 271000, Shandong, China.
| | - Guangcheng Ji
- Department of Neurology, the Third Affiliated Clinical Hospital of the Changchun University of Chinese Medicine, Boshuo Road, Changchun, 130117, Jilin, China.
| | - Mingquan Li
- Department of Neurology, the Third Affiliated Clinical Hospital of the Changchun University of Chinese Medicine, Boshuo Road, Changchun, 130117, Jilin, China.
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38
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Heuer SE, Nickerson EW, Howell GR, Bloss EB. Genetic context drives age-related disparities in synaptic maintenance and structure across cortical and hippocampal neuronal circuits. Aging Cell 2024; 23:e14033. [PMID: 38130024 PMCID: PMC10861192 DOI: 10.1111/acel.14033] [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: 08/03/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 12/23/2023] Open
Abstract
The disconnection of neuronal circuitry through synaptic loss is presumed to be a major driver of age-related cognitive decline. Age-related cognitive decline is heterogeneous, yet whether genetic mechanisms differentiate successful from unsuccessful cognitive decline through maintenance or vulnerability of synaptic connections remains unknown. Previous work using rodent and primate models leveraged various techniques to imply that age-related synaptic loss is widespread on pyramidal cells in prefrontal cortex (PFC) circuits but absent on those in area CA1 of the hippocampus. Here, we examined the effect of aging on synapses on projection neurons forming a hippocampal-cortico-thalamic circuit important for spatial working memory tasks from two genetically distinct mouse strains that exhibit susceptibility (C57BL/6J) or resistance (PWK/PhJ) to cognitive decline during aging. Across both strains, synapse density on CA1-to-PFC projection neurons appeared completely intact with age. In contrast, we found synapse loss on PFC-to-nucleus reuniens (RE) projection neurons from aged C57BL/6J but not PWK/PhJ mice. Moreover, synapses from aged PWK/PhJ mice but not from C57BL/6J exhibited altered morphologies that suggest increased efficiency to drive depolarization in the parent dendrite. Our findings suggest resistance to age-related cognitive decline results in part by age-related synaptic adaptations, and identification of these mechanisms in PWK/PhJ mice could uncover new therapeutic targets for promoting successful cognitive aging and extending human health span.
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Affiliation(s)
- Sarah E. Heuer
- The Jackson LaboratoryBar HarborMaineUSA
- Tufts University Graduate School of Biomedical SciencesBostonMassachusettsUSA
| | - Emily W. Nickerson
- The Jackson LaboratoryBar HarborMaineUSA
- Tufts University Graduate School of Biomedical SciencesBostonMassachusettsUSA
| | - Gareth R. Howell
- The Jackson LaboratoryBar HarborMaineUSA
- Tufts University Graduate School of Biomedical SciencesBostonMassachusettsUSA
- Graduate School of Biomedical Sciences and EngineeringUniversity of MaineOronoMaineUSA
| | - Erik B. Bloss
- The Jackson LaboratoryBar HarborMaineUSA
- Tufts University Graduate School of Biomedical SciencesBostonMassachusettsUSA
- Graduate School of Biomedical Sciences and EngineeringUniversity of MaineOronoMaineUSA
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39
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Yarmohammadi-Samani P, Vatanparast J. Sex-specific dendritic morphology of hippocampal pyramidal neurons in the adolescent and young adult rats. Int J Dev Neurosci 2024; 84:47-63. [PMID: 37933732 DOI: 10.1002/jdn.10307] [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: 06/17/2023] [Revised: 09/02/2023] [Accepted: 10/16/2023] [Indexed: 11/08/2023] Open
Abstract
CA1 and CA3 pyramidal neurons are the major sources of hippocampal efferents. The structural features of these neurons are presumed to be involved in various normal/abnormal cognitive and emotional outcomes by influencing the pattern of synaptic inputs and neuronal signal processing. Although many studies have described hippocampal structure differences between males and females, these reports mainly focused on gross anatomical features in adult or aged models, and such distinctions on neuronal morphology and dendritic spine density during adolescence, a period of high vulnerability to neurodevelopmental disorders, have received much less attention. In this work, we analyzed dendritic architecture and density of spines in CA1 and CA3 neurons of male and female rats in early adolescence (postnatal day, PND 40) and compared them with those in late adolescence/young adulthood (PND 60). On PND 40, CA1 neurons of male rats showed more Sholl intersections and spine density in apical and basal dendrites compared to those in females. The Sholl intersections in basal dendrites of CA3 neurons were also more in males, whereas the number of apical dendrite intersections was not significantly different between sexes. In male rats, there was a notable decrease in the number of branch and terminal points in the basal dendrite of CA1 neurons of young adults when compared to their sex-matched adolescent rats. On the other hand, CA1 neurons in young adult females also showed more Sholl intersections in apical and basal dendrites compared to adolescent females. Meanwhile, the total cable length, the number of branches, and terminal points of apical dendrites in CA3 neurons also exhibited a significant reduction in young adult male rats compared to their sex-matched adolescents. In young adult rats, both apical and basal dendrites of CA3 neurons in males showed fewer intersections with Sholl circles, but there were no significant differences in dendritic spine density or count estimation between males and females. On the other hand, young adult female rats had more Sholl intersections and dendritic spine count on the basal dendrites of CA3 neurons compared to adolescent females. Although no significant sex- and age-dependent difference in neuronal density was detected in CA1 and CA3 subareas, CA3 pyramidal neurons of both male and female rats showed reduced soma area compared to adolescent rats. Our findings show that the sex differences in the dendritic structure of CA1 and CA3 neurons vary by age and also by the compartments of dendritic arbors. Such variations in the morphology of hippocampal pyramidal neurons may take part as a basis for normal cognitive and affective differences between the sexes, as well as distinct sensitivity to interfering factors and the prevalence of neuropsychological diseases.
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Affiliation(s)
| | - Jafar Vatanparast
- Department of Biology, School of Science, Shiraz University, Shiraz, Iran
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40
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Legutko D, Kuźniewska B, Kalita K, Yasuda R, Kaczmarek L, Michaluk P. BDNF signaling requires Matrix Metalloproteinase-9 during structural synaptic plasticity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.08.569797. [PMID: 38106209 PMCID: PMC10723398 DOI: 10.1101/2023.12.08.569797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Synaptic plasticity underlies learning and memory processes as well as contributes, in its aberrant form, to neuropsychiatric disorders. One of its major forms is structural long-term potentiation (sLTP), an activity-dependent growth of dendritic spines that harbor excitatory synapses. The process depends on the release of brain-derived neurotrophic factor (BDNF), and activation of its receptor, TrkB. Matrix metalloproteinase-9 (MMP-9), an extracellular protease is essential for many forms of neuronal plasticity engaged in physiological as well as pathological processes. Here, we utilized two-photon microscopy and two-photon glutamate uncaging to demonstrate that MMP-9 activity is essential for sLTP and is rapidly (~seconds) released from dendritic spines in response to synaptic stimulation. Moreover, we show that either chemical or genetic inhibition of MMP-9 impairs TrkB activation, as measured by fluorescence lifetime imaging microscopy of FRET sensor. Furthermore, we provide evidence for a cell-free cleavage of proBDNF into mature BDNF by MMP-9. Our findings point to the autocrine mechanism of action of MMP-9 through BDNF maturation and TrkB activation during sLTP.
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Affiliation(s)
- Diana Legutko
- BRAINCITY, Laboratory of Neurobiology, The Nencki Institute, 02-093 Warsaw, Pasteura 3, Poland
- Max Planck Florida Institute for Neuroscience, 1 Max Planck Way, Jupiter, Florida 33458, USA
| | - Bożena Kuźniewska
- BRAINCITY, Laboratory of Neurobiology, The Nencki Institute, 02-093 Warsaw, Pasteura 3, Poland
- Current address: Department of Animal Physiology, Institute of Functional Biology and Ecology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Katarzyna Kalita
- BRAINCITY, Laboratory of Neurobiology, The Nencki Institute, 02-093 Warsaw, Pasteura 3, Poland
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, 1 Max Planck Way, Jupiter, Florida 33458, USA
| | - Leszek Kaczmarek
- BRAINCITY, Laboratory of Neurobiology, The Nencki Institute, 02-093 Warsaw, Pasteura 3, Poland
| | - Piotr Michaluk
- BRAINCITY, Laboratory of Neurobiology, The Nencki Institute, 02-093 Warsaw, Pasteura 3, Poland
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Clavet-Fournier V, Lee C, Wegner W, Brose N, Rhee J, Willig KI. Pre- and postsynaptic nanostructures increase in size and complexity after induction of long-term potentiation. iScience 2024; 27:108679. [PMID: 38213627 PMCID: PMC10783556 DOI: 10.1016/j.isci.2023.108679] [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: 04/18/2023] [Revised: 11/09/2023] [Accepted: 12/05/2023] [Indexed: 01/13/2024] Open
Abstract
Synapses, specialized contact sites between neurons, are the fundamental elements of neuronal information transfer. Synaptic plasticity involves changes in synaptic morphology and the number of neurotransmitter receptors, and is thought to underlie learning and memory. However, it is not clear how these structural and functional changes are connected. We utilized time-lapse super-resolution STED microscopy of organotypic hippocampal brain slices and cultured neurons to visualize structural changes of the synaptic nano-organization of the postsynaptic scaffolding protein PSD95, the presynaptic scaffolding protein Bassoon, and the GluA2 subunit of AMPA receptors by chemically induced long-term potentiation (cLTP) at the level of single synapses. We found that the nano-organization of all three proteins increased in complexity and size after cLTP induction. The increase was largely synchronous, peaking at ∼60 min after stimulation. Therefore, both the size and complexity of individual pre- and post-synaptic nanostructures serve as substrates for tuning and determining synaptic strength.
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Affiliation(s)
- Valérie Clavet-Fournier
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Göttingen Graduate Center for Neurosciences, Biophysics, und Molecular Biosciences (GGNB), Göttingen, Germany
| | - ChungKu Lee
- Department of Molecular Neurobiology, Synaptic Physiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Waja Wegner
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - JeongSeop Rhee
- Department of Molecular Neurobiology, Synaptic Physiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Katrin I. Willig
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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Wu H, Chen X, Shen Z, Li H, Liang S, Lu Y, Zhang M. Phosphorylation-dependent membraneless organelle fusion and fission illustrated by postsynaptic density assemblies. Mol Cell 2024; 84:309-326.e7. [PMID: 38096828 DOI: 10.1016/j.molcel.2023.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 09/10/2023] [Accepted: 11/13/2023] [Indexed: 01/21/2024]
Abstract
Membraneless organelles formed by phase separation of proteins and nucleic acids play diverse cellular functions. Whether and, if yes, how membraneless organelles in ways analogous to membrane-based organelles also undergo regulated fusion and fission is unknown. Here, using a partially reconstituted mammalian postsynaptic density (PSD) condensate as a paradigm, we show that membraneless organelles can undergo phosphorylation-dependent fusion and fission. Without phosphorylation of the SAPAP guanylate kinase domain-binding repeats, the upper and lower layers of PSD protein mixtures form two immiscible sub-compartments in a phase-in-phase organization. Phosphorylation of SAPAP leads to fusion of the two sub-compartments into one condensate accompanied with an increased Stargazin density in the condensate. Dephosphorylation of SAPAP can reverse this event. Preventing SAPAP phosphorylation in vivo leads to increased separation of proteins from the lower and upper layers of PSD sub-compartments. Thus, analogous to membrane-based organelles, membraneless organelles can also undergo regulated fusion and fission.
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Affiliation(s)
- Haowei Wu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xudong Chen
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Zeyu Shen
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Hao Li
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shiqi Liang
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Youming Lu
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mingjie Zhang
- Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen 518036, China; School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China.
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Samavat M, Bartol TM, Bromer C, Hubbard DD, Hanka DC, Kuwajima M, Mendenhall JM, Parker PH, Bowden JB, Abraham WC, Sejnowski TJ, Harris KM. Long-Term Potentiation Produces a Sustained Expansion of Synaptic Information Storage Capacity in Adult Rat Hippocampus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.574766. [PMID: 38260636 PMCID: PMC10802612 DOI: 10.1101/2024.01.12.574766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Long-term potentiation (LTP) has become a standard model for investigating synaptic mechanisms of learning and memory. Increasingly, it is of interest to understand how LTP affects the synaptic information storage capacity of the targeted population of synapses. Here, structural synaptic plasticity during LTP was explored using three-dimensional reconstruction from serial section electron microscopy. Storage capacity was assessed by applying a new analytical approach, Shannon information theory, to delineate the number of functionally distinguishable synaptic strengths. LTP was induced by delta-burst stimulation of perforant pathway inputs to the middle molecular layer of hippocampal dentate granule cells in adult rats. Spine head volumes were measured as predictors of synaptic strength and compared between LTP and control hemispheres at 30 min and 2 hr after the induction of LTP. Synapses from the same axon onto the same dendrite were used to determine the precision of synaptic plasticity based on the similarity of their physical dimensions. Shannon entropy was measured by exploiting the frequency of spine heads in functionally distinguishable sizes to assess the degree to which LTP altered the number of bits of information storage. Outcomes from these analyses reveal that LTP expanded storage capacity; the distribution of spine head volumes was increased from 2 bits in controls to 3 bits at 30 min and 2.7 bits at 2 hr after the induction of LTP. Furthermore, the distribution of spine head volumes was more uniform across the increased number of functionally distinguishable sizes following LTP, thus achieving more efficient use of coding space across the population of synapses.
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Affiliation(s)
- Mohammad Samavat
- Department of Electrical and Computer Engineering, Jacobs School of Engineering, UC San Diego
- Computational Neurobiology Laboratory, The Salk Institute for Biological Sciences, La Jolla, CA 92037
| | - Thomas M Bartol
- Computational Neurobiology Laboratory, The Salk Institute for Biological Sciences, La Jolla, CA 92037
| | - Cailey Bromer
- Computational Neurobiology Laboratory, The Salk Institute for Biological Sciences, La Jolla, CA 92037
| | - Dusten D Hubbard
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712
| | - Dakota C Hanka
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712
| | - Masaaki Kuwajima
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712
| | - John M Mendenhall
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712
| | - Patrick H Parker
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712
| | - Jared B Bowden
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712
- Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | - Wickliffe C Abraham
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, 9016, New Zealand
| | - Terrence J Sejnowski
- Computational Neurobiology Laboratory, The Salk Institute for Biological Sciences, La Jolla, CA 92037
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Kristen M Harris
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712
- Department of Neuroscience, The University of Texas at Austin, Austin, TX 78712
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Li H, Tamura R, Hayashi D, Asai H, Koga J, Ando S, Yokota S, Kaneko J, Sakurai K, Sumiyoshi A, Yamamoto T, Hikishima K, Tanaka KZ, McHugh TJ, Hisatsune T. Silencing dentate newborn neurons alters excitatory/inhibitory balance and impairs behavioral inhibition and flexibility. SCIENCE ADVANCES 2024; 10:eadk4741. [PMID: 38198539 PMCID: PMC10780870 DOI: 10.1126/sciadv.adk4741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 12/13/2023] [Indexed: 01/12/2024]
Abstract
Adult neurogenesis confers the hippocampus with unparalleled neural plasticity, essential for intricate cognitive functions. The specific influence of sparse newborn neurons (NBNs) in modulating neural activities and subsequently steering behavior, however, remains obscure. Using an engineered NBN-tetanus toxin mouse model (NBN-TeTX), we noninvasively silenced NBNs, elucidating their crucial role in impulse inhibition and cognitive flexibility as evidenced through Morris water maze reversal learning and Go/Nogo task in operant learning. Task-based functional MRI (tb-fMRI) paired with operant learning revealed dorsal hippocampal hyperactivation during the Nogo task in male NBN-TeTX mice, suggesting that hippocampal hyperexcitability might underlie the observed behavioral deficits. Additionally, resting-state fMRI (rs-fMRI) exhibited enhanced functional connectivity between the dorsal and ventral dentate gyrus following NBN silencing. Further investigations into the activities of PV+ interneurons and mossy cells highlighted the indispensability of NBNs in maintaining the hippocampal excitation/inhibition balance. Our findings emphasize that the neural plasticity driven by NBNs extensively modulates the hippocampus, sculpting inhibitory control and cognitive flexibility.
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Affiliation(s)
- Haowei Li
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Risako Tamura
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Daiki Hayashi
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Hirotaka Asai
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Junya Koga
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Shota Ando
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Sayumi Yokota
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Jun Kaneko
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Keisuke Sakurai
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Akira Sumiyoshi
- Department of Molecular Imaging and Theranostics, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Tadashi Yamamoto
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Keigo Hikishima
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Kazumasa Z. Tanaka
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, Saitama, Japan
| | - Thomas J. McHugh
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, Saitama, Japan
| | - Tatsuhiro Hisatsune
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
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Claiborne N, Anisimova M, Zito K. Activity-Dependent Stabilization of Nascent Dendritic Spines Requires Nonenzymatic CaMKIIα Function. J Neurosci 2024; 44:e1393222023. [PMID: 38050081 PMCID: PMC10860566 DOI: 10.1523/jneurosci.1393-22.2023] [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: 07/18/2022] [Revised: 10/18/2023] [Accepted: 11/17/2023] [Indexed: 12/06/2023] Open
Abstract
The outgrowth and stabilization of nascent dendritic spines are crucial processes underlying learning and memory. Most new spines retract shortly after growth; only a small subset is stabilized and integrated into the new circuit connections that support learning. New spine stabilization has been shown to rely upon activity-dependent molecular mechanisms that also contribute to long-term potentiation (LTP) of synaptic strength. Indeed, disruption of the activity-dependent targeting of the kinase CaMKIIα to the GluN2B subunit of the NMDA-type glutamate receptor disrupts both LTP and activity-dependent stabilization of new spines. Yet it is not known which of CaMKIIα's many enzymatic and structural functions are important for new spine stabilization. Here, we used two-photon imaging and photolysis of caged glutamate to monitor the activity-dependent stabilization of new dendritic spines on hippocampal CA1 neurons from mice of both sexes in conditions where CaMKIIα functional and structural interactions were altered. Surprisingly, we found that inhibiting CaMKIIα kinase activity either genetically or pharmacologically did not impair activity-dependent new spine stabilization. In contrast, shRNA knockdown of CaMKIIα abolished activity-dependent new spine stabilization, which was rescued by co-expressing shRNA-resistant full-length CaMKIIα, but not by a truncated monomeric CaMKIIα. Notably, overexpression of phospho-mimetic CaMKIIα-T286D, which exhibits activity-independent targeting to GluN2B, enhanced basal new spine survivorship in the absence of additional glutamatergic stimulation, even when kinase activity was disrupted. Together, our results support a model in which nascent dendritic spine stabilization requires structural and scaffolding interactions mediated by dodecameric CaMKIIα that are independent of its enzymatic activities.
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Affiliation(s)
- Nicole Claiborne
- Center for Neuroscience, University of California, Davis, California 95618
| | | | - Karen Zito
- Center for Neuroscience, University of California, Davis, California 95618
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Bapat O, Purimetla T, Kruessel S, Shah M, Fan R, Thum C, Rupprecht F, Langer JD, Rangaraju V. VAP spatially stabilizes dendritic mitochondria to locally support synaptic plasticity. Nat Commun 2024; 15:205. [PMID: 38177103 PMCID: PMC10766606 DOI: 10.1038/s41467-023-44233-8] [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: 02/06/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
Synapses are pivotal sites of plasticity and memory formation. Consequently, synapses are energy consumption hotspots susceptible to dysfunction when their energy supplies are perturbed. Mitochondria are stabilized near synapses via the cytoskeleton and provide the local energy required for synaptic plasticity. However, the mechanisms that tether and stabilize mitochondria to support synaptic plasticity are unknown. We identified proteins exclusively tethering mitochondria to actin near postsynaptic spines. We find that VAP, the vesicle-associated membrane protein-associated protein implicated in amyotrophic lateral sclerosis, stabilizes mitochondria via actin near the spines. To test if the VAP-dependent stable mitochondrial compartments can locally support synaptic plasticity, we used two-photon glutamate uncaging for spine plasticity induction and investigated the induced and adjacent uninduced spines. We find VAP functions as a spatial stabilizer of mitochondrial compartments for up to ~60 min and as a spatial ruler determining the ~30 μm dendritic segment supported during synaptic plasticity.
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Affiliation(s)
- Ojasee Bapat
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- International Max Planck Research School for Synapses and Circuits, Jupiter, FL, 33458, USA
| | - Tejas Purimetla
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- Geisel School of Medicine at Dartmouth, Hanover, NH, 03755-1404, USA
| | - Sarah Kruessel
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Monil Shah
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- International Max Planck Research School for Synapses and Circuits, Jupiter, FL, 33458, USA
| | - Ruolin Fan
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Christina Thum
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
| | - Fiona Rupprecht
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Max Planck Institute of Biophysics, Frankfurt, 60438, Germany
- Thermo Fisher Diagnostics GmbH, Henningsdorf, 16761, Germany
| | - Julian D Langer
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Max Planck Institute of Biophysics, Frankfurt, 60438, Germany
| | - Vidhya Rangaraju
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA.
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47
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Brown KA, Gould TD. Targeting metaplasticity mechanisms to promote sustained antidepressant actions. Mol Psychiatry 2024:10.1038/s41380-023-02397-1. [PMID: 38177353 DOI: 10.1038/s41380-023-02397-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024]
Abstract
The discovery that subanesthetic doses of (R, S)-ketamine (ketamine) and (S)-ketamine (esketamine) rapidly induce antidepressant effects and promote sustained actions following drug clearance in depressed patients who are treatment-resistant to other therapies has resulted in a paradigm shift in the conceptualization of how rapidly and effectively depression can be treated. Consequently, the mechanism(s) that next generation antidepressants may engage to improve pathophysiology and resultant symptomology are being reconceptualized. Impaired excitatory glutamatergic synapses in mood-regulating circuits are likely a substantial contributor to the pathophysiology of depression. Metaplasticity is the process of regulating future capacity for plasticity by priming neurons with a stimulation that alters later neuronal plasticity responses. Accordingly, the development of treatment modalities that specifically modulate the duration, direction, or magnitude of glutamatergic synaptic plasticity events such as long-term potentiation (LTP), defined here as metaplastogens, may be an effective approach to reverse the pathophysiology underlying depression and improve depression symptoms. We review evidence that the initiating mechanisms of pharmacologically diverse rapid-acting antidepressants (i.e., ketamine mimetics) converge on consistent downstream molecular mediators that facilitate the expression/maintenance of increased synaptic strength and resultant persisting antidepressant effects. Specifically, while the initiating mechanisms of these therapies may differ (e.g., cell type-specificity, N-methyl-D-aspartate receptor (NMDAR) subtype-selective inhibition vs activation, metabotropic glutamate receptor 2/3 antagonism, AMPA receptor potentiation, 5-HT receptor-activating psychedelics, etc.), the sustained therapeutic mechanisms of putative rapid-acting antidepressants will be mediated, in part, by metaplastic effects that converge on consistent molecular mediators to enhance excitatory neurotransmission and altered capacity for synaptic plasticity. We conclude that the convergence of these therapeutic mechanisms provides the opportunity for metaplasticity processes to be harnessed as a druggable plasticity mechanism by next-generation therapeutics. Further, targeting metaplastic mechanisms presents therapeutic advantages including decreased dosing frequency and associated diminished adverse responses by eliminating the requirement for the drug to be continuously present.
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Affiliation(s)
- Kyle A Brown
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Todd D Gould
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Veterans Affairs Maryland Health Care System, Baltimore, MD, 21201, USA.
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Aziz HC, Mangieri RA. Sexually dimorphic characteristics of dopamine D1 receptor-expressing neurons within the shell of the nucleus accumbens of adolescent mice. RESEARCH SQUARE 2023:rs.3.rs-3717874. [PMID: 38168228 PMCID: PMC10760258 DOI: 10.21203/rs.3.rs-3717874/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Background Adolescence, a developmental stage, is characterized by psychosocial and biological changes. The nucleus accumbens (NAc), a striatal brain region composed of the core (NAcC) and shell (NAcSh), has been linked to risk-taking behavior and implicated in reward seeking and evaluation. Most neurons in the NAc are medium spiny neurons (MSNs) that express dopamine D1 receptors (D1R+) and/or dopamine D2 receptors (D2R+). Changes in dopaminergic and glutamatergic systems occur during adolescence and converge in the NAc. While there are previous investigations into sex differences in membrane excitability and synaptic glutamate transmission in both subdivisions of the NAc, to our knowledge, none have specified NAcSh D1R+MSNs from mice during mid-adolescence. Methods Sagittal brain slices containing the NAc were prepared from B6.Cg-Tg(Drd1a-tdTomato)6Calak/J mice of both sexes from postnatal days 35-47. Stained smears were made from vaginal samples from female mice to identify the stage of Estrous at death. Whole-cell electrophysiology recordings were collected from NAcSh D1R+MSNs in the form of membrane-voltage responses to current injections and spontaneous excitatory postsynaptic currents (sEPSCs). Results The action potential duration was longer in males than infemales. Additionally, the frequency of sEPSCs was higher in females, and the mean event amplitude was smaller than that in males. We found no evidence of the observed sex differences being driven by the stage of the Estrous cycle and no physiological parameter significantly varied with respect to the Estrous cycle. Conclusions Taken together, our results indicate that NAcSh D1R+MSNs exhibit sex differences during mid-adolescence that are independent of the stage of Estrous, in both AP waveform and glutamate transmission, possibly due to changes in voltage-gated potassium channels and α-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors, respectively.
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Caiola HO, Wu Q, Soni S, Wang XF, Monahan K, Pang ZP, Wagner GC, Zhang H. Neuronal connectivity, behavioral, and transcriptional alterations associated with the loss of MARK2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.569759. [PMID: 38105965 PMCID: PMC10723285 DOI: 10.1101/2023.12.05.569759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Neuronal connectivity is essential for adaptive brain responses and can be modulated by dendritic spine plasticity and the intrinsic excitability of individual neurons. Dysregulation of these processes can lead to aberrant neuronal activity, which has been associated with numerous neurological disorders including autism, epilepsy, and Alzheimer's disease. Nonetheless, the molecular mechanisms underlying aberrant neuronal connectivity remains unclear. We previously found that the serine/threonine kinase Microtubule Affinity Regulating Kinase 2 (MARK2), also known as Partitioning Defective 1b (Par1b), is important for the formation of dendritic spines in vitro. However, despite its genetic association with several neurological disorders, the in vivo impact of MARK2 on neuronal connectivity and cognitive functions remains unclear. Here, we demonstrate that loss of MARK2 in vivo results in changes to dendritic spine morphology, which in turn leads to a decrease in excitatory synaptic transmission. Additionally, loss of MARK2 produces substantial impairments in learning and memory, anxiety, and social behavior. Notably, MARK2 deficiency results in heightened seizure susceptibility. Consistent with this observation, RNAseq analysis reveals transcriptional changes in genes regulating synaptic transmission and ion homeostasis. These findings underscore the in vivo role of MARK2 in governing synaptic connectivity, cognitive functions, and seizure susceptibility.
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50
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Knobloch JA, Laurent G, Lauterbach MA. STED microscopy reveals dendrite-specificity of spines in turtle cortex. Prog Neurobiol 2023; 231:102541. [PMID: 37898315 DOI: 10.1016/j.pneurobio.2023.102541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 10/20/2023] [Accepted: 10/21/2023] [Indexed: 10/30/2023]
Abstract
Dendritic spines are key structures for neural communication, learning and memory. Spine size and shape probably reflect synaptic strength and learning. Imaging with superresolution STED microscopy the detailed shape of the majority of the spines of individual neurons in turtle cortex (Trachemys scripta elegans) revealed several distinguishable shape classes. Dendritic spines of a given class were not distributed randomly, but rather decorated significantly more often some dendrites than others. The individuality of dendrites was corroborated by significant inter-dendrite differences in other parameters such as spine density and length. In addition, many spines were branched or possessed spinules. These findings may have implications for the role of individual dendrites in this cortex.
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Affiliation(s)
- Jan A Knobloch
- Department of Molecular Imaging, Center for Integrative Physiology and Molecular Medicine, Saarland University, Building 48, 66421 Homburg, Germany
| | - Gilles Laurent
- Max Planck Institute for Brain Research, Max-von-Laue-Str. 4, 60438 Frankfurt am Main, Germany
| | - Marcel A Lauterbach
- Department of Molecular Imaging, Center for Integrative Physiology and Molecular Medicine, Saarland University, Building 48, 66421 Homburg, Germany; Max Planck Institute for Brain Research, Max-von-Laue-Str. 4, 60438 Frankfurt am Main, Germany.
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