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Control of Synapse Structure and Function by Actin and Its Regulators. Cells 2022; 11:cells11040603. [PMID: 35203254 PMCID: PMC8869895 DOI: 10.3390/cells11040603] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/30/2022] [Accepted: 02/06/2022] [Indexed: 02/07/2023] Open
Abstract
Neurons transmit and receive information at specialized junctions called synapses. Excitatory synapses form at the junction between a presynaptic axon terminal and a postsynaptic dendritic spine. Supporting the shape and function of these junctions is a complex network of actin filaments and its regulators. Advances in microscopic techniques have enabled studies of the organization of actin at synapses and its dynamic regulation. In addition to highlighting recent advances in the field, we will provide a brief historical perspective of the understanding of synaptic actin at the synapse. We will also highlight key neuronal functions regulated by actin, including organization of proteins in the pre- and post- synaptic compartments and endocytosis of ion channels. We review the evidence that synapses contain distinct actin pools that differ in their localization and dynamic behaviors and discuss key functions for these actin pools. Finally, whole exome sequencing of humans with neurodevelopmental and psychiatric disorders has identified synaptic actin regulators as key disease risk genes. We briefly summarize how genetic variants in these genes impact neurotransmission via their impact on synaptic actin.
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Becker-Krail DD, Parekh PK, Ketchesin KD, Yamaguchi S, Yoshino J, Hildebrand MA, Dunham B, Ganapathiraiu MK, Logan RW, McClung CA. Circadian transcription factor NPAS2 and the NAD + -dependent deacetylase SIRT1 interact in the mouse nucleus accumbens and regulate reward. Eur J Neurosci 2022; 55:675-693. [PMID: 35001440 PMCID: PMC9355311 DOI: 10.1111/ejn.15596] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 12/14/2021] [Accepted: 01/06/2022] [Indexed: 02/03/2023]
Abstract
Substance use disorders are associated with disruptions to both circadian rhythms and cellular metabolic state. At the molecular level, the circadian molecular clock and cellular metabolic state may be interconnected through interactions with the nicotinamide adenine dinucleotide (NAD+ )-dependent deacetylase, sirtuin 1 (SIRT1). In the nucleus accumbens (NAc), a region important for reward, both SIRT1 and the circadian transcription factor neuronal PAS domain protein 2 (NPAS2) are highly enriched, and both are regulated by the metabolic cofactor NAD+ . Substances of abuse, like cocaine, greatly disrupt cellular metabolism and promote oxidative stress; however, their effects on NAD+ in the brain remain unclear. Interestingly, cocaine also induces NAc expression of both NPAS2 and SIRT1, and both have independently been shown to regulate cocaine reward in mice. However, whether NPAS2 and SIRT1 interact in the NAc and/or whether together they regulate reward is unknown. Here, we demonstrate diurnal expression of Npas2, Sirt1 and NAD+ in the NAc, which is altered by cocaine-induced upregulation. Additionally, co-immunoprecipitation reveals NPAS2 and SIRT1 interact in the NAc, and cross-analysis of NPAS2 and SIRT1 chromatin immunoprecipitation sequencing reveals several reward-relevant and metabolic-related pathways enriched among shared gene targets. Notably, NAc-specific Npas2 knock-down or a functional Npas2 mutation in mice attenuates SIRT1-mediated increases in cocaine preference. Together, our data reveal an interaction between NPAS2 and SIRT1 in the NAc, which may serve to integrate cocaine's effects on circadian and metabolic factors, leading to regulation of drug reward.
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Affiliation(s)
- Darius D. Becker-Krail
- Translational Neuroscience Program, Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA,Center for Neuroscience, University of Pittsburgh, PA, USA
| | - Puja K. Parekh
- Translational Neuroscience Program, Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA,Center for Neuroscience, University of Pittsburgh, PA, USA
| | - Kyle D. Ketchesin
- Translational Neuroscience Program, Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA,Center for Neuroscience, University of Pittsburgh, PA, USA
| | - Shintaro Yamaguchi
- Center for Human Nutrition, Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Jun Yoshino
- Center for Human Nutrition, Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Mariah A. Hildebrand
- Translational Neuroscience Program, Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA,Center for Neuroscience, University of Pittsburgh, PA, USA
| | - Brandon Dunham
- Department of Biomedical Informatics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Madhavi K. Ganapathiraiu
- Department of Biomedical Informatics, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ryan W. Logan
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA
| | - Colleen A. McClung
- Translational Neuroscience Program, Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA,Center for Neuroscience, University of Pittsburgh, PA, USA,Correspondence: Colleen A. McClung,
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3
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Li ZZ, Han WJ, Sun ZC, Chen Y, Sun JY, Cai GH, Liu WN, Wang TZ, Xie YD, Mao HH, Wang F, Ma SB, Wang FD, Xie RG, Wu SX, Luo C. Extracellular matrix protein laminin β1 regulates pain sensitivity and anxiodepression-like behaviors in mice. J Clin Invest 2021; 131:e146323. [PMID: 34156983 DOI: 10.1172/jci146323] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 06/16/2021] [Indexed: 01/11/2023] Open
Abstract
Patients with neuropathic pain often experience comorbid psychiatric disorders. Cellular plasticity in the anterior cingulate cortex (ACC) is assumed to be a critical interface for pain perception and emotion. However, substantial efforts have thus far been focused on the intracellular mechanisms of plasticity rather than the extracellular alterations that might trigger and facilitate intracellular changes. Laminin, a key element of the extracellular matrix (ECM), consists of one α-, one β-, and one γ-chain and is implicated in several pathophysiological processes. Here, we showed in mice that laminin β1 (LAMB1) in the ACC was significantly downregulated upon peripheral neuropathy. Knockdown of LAMB1 in the ACC exacerbated pain sensitivity and induced anxiety and depression. Mechanistic analysis revealed that loss of LAMB1 caused actin dysregulation via interaction with integrin β1 and the subsequent Src-dependent RhoA/LIMK/cofilin pathway, leading to increased presynaptic transmitter release probability and abnormal postsynaptic spine remodeling, which in turn orchestrated the structural and functional plasticity of pyramidal neurons and eventually resulted in pain hypersensitivity and anxiodepression. This study sheds new light on the functional capability of ECM LAMB1 in modulating pain plasticity and identifies a mechanism that conveys extracellular alterations to intracellular plasticity. Moreover, we identified cingulate LAMB1/integrin β1 signaling as a promising therapeutic target for the treatment of neuropathic pain and associated anxiodepression.
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Affiliation(s)
- Zhen-Zhen Li
- Department of Neurobiology, School of Basic Medicine.,Department of Neurosurgery, Xijing Hospital, and
| | - Wen-Juan Han
- Department of Neurobiology, School of Basic Medicine
| | - Zhi-Chuan Sun
- Department of Neurobiology, School of Basic Medicine
| | - Yun Chen
- The Second Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Jun-Yi Sun
- The Second Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Guo-Hong Cai
- Department of Neurobiology, School of Basic Medicine
| | - Wan-Neng Liu
- Department of Neurobiology, School of Basic Medicine.,College of Life Sciences, Northwest University, Xi'an, China
| | - Tao-Zhi Wang
- Department of Neurobiology, School of Basic Medicine.,Department of Anesthesiology, The Second Hospital of Jilin University, Changchun, China
| | - Yang-Dan Xie
- The Second Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Hong-Hui Mao
- Department of Neurobiology, School of Basic Medicine
| | - Fei Wang
- Department of Neurobiology, School of Basic Medicine.,Medical Experiment Center, Shaanxi University of Chinese Medicine, China
| | - Sui-Bin Ma
- Department of Neurobiology, School of Basic Medicine
| | - Fu-Dong Wang
- Department of Neurobiology, School of Basic Medicine
| | - Rou-Gang Xie
- Department of Neurobiology, School of Basic Medicine
| | - Sheng-Xi Wu
- Department of Neurobiology, School of Basic Medicine
| | - Ceng Luo
- Department of Neurobiology, School of Basic Medicine
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Bączyńska E, Pels KK, Basu S, Włodarczyk J, Ruszczycki B. Quantification of Dendritic Spines Remodeling under Physiological Stimuli and in Pathological Conditions. Int J Mol Sci 2021; 22:4053. [PMID: 33919977 PMCID: PMC8070910 DOI: 10.3390/ijms22084053] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 12/14/2022] Open
Abstract
Numerous brain diseases are associated with abnormalities in morphology and density of dendritic spines, small membranous protrusions whose structural geometry correlates with the strength of synaptic connections. Thus, the quantitative analysis of dendritic spines remodeling in microscopic images is one of the key elements towards understanding mechanisms of structural neuronal plasticity and bases of brain pathology. In the following article, we review experimental approaches designed to assess quantitative features of dendritic spines under physiological stimuli and in pathological conditions. We compare various methodological pipelines of biological models, sample preparation, data analysis, image acquisition, sample size, and statistical analysis. The methodology and results of relevant experiments are systematically summarized in a tabular form. In particular, we focus on quantitative data regarding the number of animals, cells, dendritic spines, types of studied parameters, size of observed changes, and their statistical significance.
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Affiliation(s)
- Ewa Bączyńska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland; (E.B.); (K.K.P.); (J.W.)
| | - Katarzyna Karolina Pels
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland; (E.B.); (K.K.P.); (J.W.)
| | - Subhadip Basu
- Department of Computer Science and Engineering, Jadvapur University, Kolkata 700032, India;
| | - Jakub Włodarczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland; (E.B.); (K.K.P.); (J.W.)
| | - Błażej Ruszczycki
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland; (E.B.); (K.K.P.); (J.W.)
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Abl2:Cortactin Interactions Regulate Dendritic Spine Stability via Control of a Stable Filamentous Actin Pool. J Neurosci 2021; 41:3068-3081. [PMID: 33622779 DOI: 10.1523/jneurosci.2472-20.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/15/2021] [Accepted: 02/16/2021] [Indexed: 11/21/2022] Open
Abstract
Dendritic spines act as the receptive contacts at most excitatory synapses. Spines are enriched in a network of actin filaments comprised of two kinetically distinct pools. The majority of spine actin is highly dynamic and regulates spine size, structural plasticity, and postsynaptic density organization. The remainder of the spine actin network is more stable, but the function of this minor actin population is not well understood, as tools to study it have not been available. Previous work has shown that disruption of the Abl2/Arg nonreceptor tyrosine kinase in mice compromises spine stability and size. Here, using cultured hippocampal neurons pooled from both sexes of mice, we provide evidence that binding to cortactin tethers Abl2 in spines, where Abl2 and cortactin maintain the small pool of stable actin required for dendritic spine stability. Using fluorescence recovery after photobleaching of GFP-actin, we find that disruption of Abl2:cortactin interactions eliminates stable actin filaments in dendritic spines, significantly reducing spine density. A subset of spines remaining after Abl2 depletion retain their stable actin pool and undergo activity-dependent spine enlargement, associated with increased cortactin and GluN2B levels. Finally, tonic increases in synaptic activity rescue spine loss following Abl2 depletion by promoting cortactin enrichment in vulnerable spines. Together, our findings strongly suggest that Abl2:cortactin interactions promote spine stability by maintaining pools of stable actin filaments in spines.SIGNIFICANCE STATEMENT Dendritic spines contain two kinetically distinct pools of actin. The more abundant, highly dynamic pool regulates spine shape, size, and plasticity. The function of the smaller, stable actin network is not well understood, as tools to study it have not been available. We demonstrate here that Abl2 and its substrate and interaction partner, cortactin, are essential to maintain the stable pool in spines. Depletion of the stable actin pool via disruption of Abl2 or cortactin, or interactions between the proteins, significantly reduces spine stability. We also provide evidence that tonic increases in synaptic activity promote spine stability via enrichment of cortactin in spines, suggesting that synaptic activity acts on the stable actin pool to stabilize dendritic spines.
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Szabó LE, Marcello GM, Süth M, Sótonyi P, Rácz B. Distribution of cortactin in cerebellar Purkinje cell spines. Sci Rep 2021; 11:1375. [PMID: 33446758 PMCID: PMC7809465 DOI: 10.1038/s41598-020-80469-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 12/22/2020] [Indexed: 01/29/2023] Open
Abstract
Dendritic spines are the primary sites of excitatory transmission in the mammalian brain. Spines of cerebellar Purkinje Cells (PCs) are plastic, but they differ from forebrain spines in a number of important respects, and the mechanisms of spine plasticity differ between forebrain and cerebellum. Our previous studies indicate that in hippocampal spines cortactin-a protein that stabilizes actin branch points-resides in the spine core, avoiding the spine shell. To see whether the distribution of cortactin differs in PC spines, we examined its subcellular organization using quantitative preembedding immunoelectron microscopy. We found that cortactin was enriched in the spine shell, associated with the non-synaptic membrane, and was also situated within the postsynaptic density (PSD). This previously unrecognized distribution of cortactin within PC spines may underlie structural and functional differences in excitatory spine synapses between forebrain, and cerebellum.
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Affiliation(s)
- Lilla E. Szabó
- grid.483037.b0000 0001 2226 5083Department of Anatomy and Histology, University of Veterinary Medicine Budapest, István u. 2., 1078 Budapest, Hungary
| | - G. Mark Marcello
- grid.483037.b0000 0001 2226 5083Department of Anatomy and Histology, University of Veterinary Medicine Budapest, István u. 2., 1078 Budapest, Hungary
| | - Miklós Süth
- grid.483037.b0000 0001 2226 5083Department of Anatomy and Histology, University of Veterinary Medicine Budapest, István u. 2., 1078 Budapest, Hungary
| | - Péter Sótonyi
- grid.483037.b0000 0001 2226 5083Department of Anatomy and Histology, University of Veterinary Medicine Budapest, István u. 2., 1078 Budapest, Hungary
| | - Bence Rácz
- grid.483037.b0000 0001 2226 5083Department of Anatomy and Histology, University of Veterinary Medicine Budapest, István u. 2., 1078 Budapest, Hungary
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Hu HT, Huang TN, Hsueh YP. KLHL17/Actinfilin, a brain-specific gene associated with infantile spasms and autism, regulates dendritic spine enlargement. J Biomed Sci 2020; 27:103. [PMID: 33256713 PMCID: PMC7708131 DOI: 10.1186/s12929-020-00696-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/23/2020] [Indexed: 11/10/2022] Open
Abstract
Background Dendritic spines, the actin-rich protrusions emerging from dendrites, are the subcellular locations of excitatory synapses in the mammalian brain. Many actin-regulating molecules modulate dendritic spine morphology. Since dendritic spines are neuron-specific structures, it is reasonable to speculate that neuron-specific or -predominant factors are involved in dendritic spine formation. KLHL17 (Kelch-like 17, also known as Actinfilin), an actin-binding protein, is predominantly expressed in brain. Human genetic study has indicated an association of KLHL17/Actinfilin with infantile spasms, a rare form of childhood epilepsy also resulting in autism and mental retardation, indicating that KLHL17/Actinfilin plays a role in neuronal function. However, it remains elusive if and how KLHL17/Actinfilin regulates neuronal development and brain function. Methods Fluorescent immunostaining and electrophysiological recording were performed to evaluate dendritic spine formation and activity in cultured hippocampal neurons. Knockdown and knockout of KLHL17/Actinfilin and expression of truncated fragments of KLHL17/Actinfilin were conducted to investigate the function of KLHL17/Actinfilin in neurons. Mouse behavioral assays were used to evaluate the role of KLHL17/Actinfilin in brain function. Results We found that KLHL17/Actinfilin tends to form circular puncta in dendritic spines and are surrounded by or adjacent to F-actin. Klhl17 deficiency impairs F-actin enrichment at dendritic spines. Knockdown and knockout of KLHL17/Actinfilin specifically impair dendritic spine enlargement, but not the density or length of dendritic spines. Both N-terminal Broad-Complex, Tramtrack and Bric-a-brac (BTB) domain and C-terminal Kelch domains of KLHL17/Actinfilin are required for F-actin remodeling and enrichment at dendritic spines, as well as dendritic spine enlargement. A reduction of postsynaptic and presynsptic markers at dendritic spines and altered mEPSC profiles due to Klhl17 deficiency evidence impaired synaptic activity in Klhl17-deficient neurons. Our behavioral assays further indicate that Klhl17 deficiency results in hyperactivity and reduced social interaction, strengthening evidence for the physiological role of KLHL17/Actinfilin. Conclusion Our findings provide evidence that KLHL17/Actinfilin modulates F-actin remodeling and contributes to regulation of neuronal morphogenesis, maturation and activity, which is likely relevant to behavioral impairment in Klhl17-deficient mice. Trial registration Non-applicable.
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Affiliation(s)
- Hsiao-Tang Hu
- Institute of Molecular Biology, Academia Sinica, 128, Academia Road, Section 2, Taipei, 11529, Taiwan, Republic of China
| | - Tzyy-Nan Huang
- Institute of Molecular Biology, Academia Sinica, 128, Academia Road, Section 2, Taipei, 11529, Taiwan, Republic of China
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, 128, Academia Road, Section 2, Taipei, 11529, Taiwan, Republic of China.
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8
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Bonilla-Quintana M, Wörgötter F, Tetzlaff C, Fauth M. Modeling the Shape of Synaptic Spines by Their Actin Dynamics. Front Synaptic Neurosci 2020; 12:9. [PMID: 32218728 PMCID: PMC7078677 DOI: 10.3389/fnsyn.2020.00009] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 02/24/2020] [Indexed: 01/05/2023] Open
Abstract
Dendritic spines are the morphological basis of excitatory synapses in the cortex and their size and shape correlates with functional synaptic properties. Recent experiments show that spines exhibit large shape fluctuations that are not related to activity-dependent plasticity but nonetheless might influence memory storage at their synapses. To investigate the determinants of such spontaneous fluctuations, we propose a mathematical model for the dynamics of the spine shape and analyze it in 2D-related to experimental microscopic imagery-and in 3D. We show that the spine shape is governed by a local imbalance between membrane tension and the expansive force from actin bundles that originates from discrete actin polymerization foci. Experiments have shown that only few such polymerization foci co-exist at any time in a spine, each having limited life time. The model shows that the momentarily existing set of such foci pushes the membrane along certain directions until foci are replaced and other directions may now be affected. We explore these relations in depth and use our model to predict shape and temporal characteristics of spines from the different biophysical parameters involved in actin polymerization. Approximating the model by a single recursive equation we finally demonstrate that the temporal evolution of the number of active foci is sufficient to predict the size of the model-spines. Thus, our model provides the first platform to study the relation between molecular and morphological properties of the spine with a high degree of biophysical detail.
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Affiliation(s)
- Mayte Bonilla-Quintana
- Department for Computational Neuroscience, Third Institute of Physics-Biophysics, Georg-August-University, Göttingen, Germany
| | - Florentin Wörgötter
- Department for Computational Neuroscience, Third Institute of Physics-Biophysics, Georg-August-University, Göttingen, Germany
- Bernstein Center for Computational Neuroscience, Georg-August-University, Göttingen, Germany
| | - Christian Tetzlaff
- Department for Computational Neuroscience, Third Institute of Physics-Biophysics, Georg-August-University, Göttingen, Germany
- Bernstein Center for Computational Neuroscience, Georg-August-University, Göttingen, Germany
| | - Michael Fauth
- Department for Computational Neuroscience, Third Institute of Physics-Biophysics, Georg-August-University, Göttingen, Germany
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9
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Artificial Intelligence and the detection of pediatric concussion using epigenomic analysis. Brain Res 2019; 1726:146510. [PMID: 31628932 DOI: 10.1016/j.brainres.2019.146510] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/14/2019] [Accepted: 10/15/2019] [Indexed: 12/12/2022]
Abstract
Concussion, also referred to as mild traumatic brain injury (mTBI) is the most common type of traumatic brain injury. Currently concussion is an area ofintensescientific interest to better understand the biological mechanisms and for biomarker development. We evaluated whole genome-wide blood DNA cytosine ('CpG') methylation in 17 pediatric concussion isolated cases and 18 unaffected controls using Illumina Infinium MethylationEPIC assay. Pathway analysis was performed using Ingenuity Pathway Analysis to help elucidate the epigenetic and molecular mechanisms of the disorder. Area under the receiver operating characteristics (AUC) curves and FDR p-values were calculated for mTBI detection based on CpG methylation levels. Multiple Artificial Intelligence (AI) platforms including Deep Learning (DL), the newest form of AI, were used to predict concussion based on i) CpG methylation markers alone, and ii) combined epigenetic, clinical and demographic predictors. We found 449 CpG sites (473 genes), those were statistically significantly methylated in mTBI compared to controls. There were four CpGs with excellent individual accuracy (AUC ≥ 0.90-1.00) while 119 displayed good accuracy (AUC ≥ 0.80-0.89) for the prediction of mTBI. The CpG methylation changes ≥10% were observed in many CpG loci after concussion suggesting biological significance. Pathway analysis identified several biologically important neurological pathways that were perturbed including those associated with: impaired brain function, cognition, memory, neurotransmission, intellectual disability and behavioral change and associated disorders. The combination of epigenomic and clinical predictors were highly accurate for the detection of concusion using AI techniques. Using DL/AI, a combination of epigenomic and clinical markers had sensitivity and specificity ≧95% for prediction of mTBI. In this novel study, we identified significant methylation changes in multiple genes in response to mTBI. Gene pathways that were epigenetically dysregulated included several known to be involved in neurological function, thus giving biological plausibility to our findings.
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10
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Bagni C, Zukin RS. A Synaptic Perspective of Fragile X Syndrome and Autism Spectrum Disorders. Neuron 2019; 101:1070-1088. [PMID: 30897358 PMCID: PMC9628679 DOI: 10.1016/j.neuron.2019.02.041] [Citation(s) in RCA: 186] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/25/2019] [Accepted: 02/27/2019] [Indexed: 12/28/2022]
Abstract
Altered synaptic structure and function is a major hallmark of fragile X syndrome (FXS), autism spectrum disorders (ASDs), and other intellectual disabilities (IDs), which are therefore classified as synaptopathies. FXS and ASDs, while clinically and genetically distinct, share significant comorbidity, suggesting that there may be a common molecular and/or cellular basis, presumably at the synapse. In this article, we review brain architecture and synaptic pathways that are dysregulated in FXS and ASDs, including spine architecture, signaling in synaptic plasticity, local protein synthesis, (m)RNA modifications, and degradation. mRNA repression is a powerful mechanism for the regulation of synaptic structure and efficacy. We infer that there is no single pathway that explains most of the etiology and discuss new findings and the implications for future work directed at improving our understanding of the pathogenesis of FXS and related ASDs and the design of therapeutic strategies to ameliorate these disorders.
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Affiliation(s)
- Claudia Bagni
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.
| | - R Suzanne Zukin
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York City, NY, USA.
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11
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Shin MS, Song SH, Shin JE, Lee SH, Huh SO, Park D. Src-mediated phosphorylation of βPix-b regulates dendritic spine morphogenesis. J Cell Sci 2019; 132:jcs.224980. [DOI: 10.1242/jcs.224980] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/24/2018] [Indexed: 11/20/2022] Open
Abstract
PAK-interacting guanine nucleotide exchange factor (βPix) has been implicated in many actin-based cellular processes including spine morphogenesis in neurons. However, the molecular mechanisms by which βPix controls spine morphology remain elusive. Previously, we have reported the expression of several alternative spliced βPix isoforms in the brain. Here, we report a novel finding that the b isoform of βPix (βPix-b) mediates regulation of spine and synapse formation. We found that βPix-b, which is mainly expressed in neurons, enhances spine and synapse formation through preferential localization at spines. In neurons, glutamate treatment efficiently stimulates Rac1 GEF activity of βPix-b. The glutamate stimulation also promotes Src kinase-mediated phosphorylation of βPix-b in both AMPA receptor- and NMDA receptor-dependent manner. Tyrosine 598 (Y598) of βPix-b is identified as the major Src-mediated phosphorylation site. Finally, Y598 phosphorylation of βPix-b enhances its Rac1 GEF activity that is critical for spine and synapse formation. In conclusion, we provide a novel mechanism by which βPix-b regulates activity-dependent spinogenesis and synaptogenesis via Src-mediated phosphorylation.
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Affiliation(s)
- Mi-seon Shin
- School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Sang-ho Song
- School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
- Current address: Lee Kong Chian School of Medicine, Nanyang Technological University and Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Jung Eun Shin
- School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
- Current address: KU Advanced Graduate Program for Life Science, Korea University, Seoul 02841, Republic of Korea
| | - Seung-Hye Lee
- School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
- Current address: Department of Neuroscience, Genentech, Inc., South San Francisco, CA 94080, USA
| | - Sung-Oh Huh
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chuncheon 24252, Republic of Korea
| | - Dongeun Park
- School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
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Saul MC, Blatti C, Yang W, Bukhari SA, Shpigler HY, Troy JM, Seward CH, Sloofman L, Chandrasekaran S, Bell AM, Stubbs L, Robinson GE, Zhao SD, Sinha S. Cross-species systems analysis of evolutionary toolkits of neurogenomic response to social challenge. GENES BRAIN AND BEHAVIOR 2018; 18:e12502. [PMID: 29968347 DOI: 10.1111/gbb.12502] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/18/2018] [Accepted: 06/20/2018] [Indexed: 12/15/2022]
Abstract
Social challenges like territorial intrusions evoke behavioral responses in widely diverging species. Recent work has showed that evolutionary "toolkits"-genes and modules with lineage-specific variations but deep conservation of function-participate in the behavioral response to social challenge. Here, we develop a multispecies computational-experimental approach to characterize such a toolkit at a systems level. Brain transcriptomic responses to social challenge was probed via RNA-seq profiling in three diverged species-honey bees, mice and three-spined stickleback fish-following a common methodology, allowing fair comparisons across species. Data were collected from multiple brain regions and multiple time points after social challenge exposure, achieving anatomical and temporal resolution substantially greater than previous work. We developed statistically rigorous analyses equipped to find homologous functional groups among these species at the levels of individual genes, functional and coexpressed gene modules, and transcription factor subnetworks. We identified six orthogroups involved in response to social challenge, including groups represented by mouse genes Npas4 and Nr4a1, as well as common modulation of systems such as transcriptional regulators, ion channels, G-protein-coupled receptors and synaptic proteins. We also identified conserved coexpression modules enriched for mitochondrial fatty acid metabolism and heat shock that constitute the shared neurogenomic response. Our analysis suggests a toolkit wherein nuclear receptors, interacting with chaperones, induce transcriptional changes in mitochondrial activity, neural cytoarchitecture and synaptic transmission after social challenge. It shows systems-level mechanisms that have been repeatedly co-opted during evolution of analogous behaviors, thus advancing the genetic toolkit concept beyond individual genes.
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Affiliation(s)
- Michael C Saul
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Charles Blatti
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Wei Yang
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Syed A Bukhari
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Interdisciplinary Informatics Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Hagai Y Shpigler
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Ecology, Evolution and Behavior, Hebrew University, Jerusalem, Israel
| | - Joseph M Troy
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Interdisciplinary Informatics Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Christopher H Seward
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Laura Sloofman
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Genetics and Genomic Sciences, Mount Sinai Health System, New York, New York
| | | | - Alison M Bell
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Interdisciplinary Informatics Program, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Animal Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Lisa Stubbs
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Interdisciplinary Informatics Program, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Gene E Robinson
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Sihai D Zhao
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Statistics, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Saurabh Sinha
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, Illinois
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13
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Lin YC, Frei JA, Kilander MBC, Shen W, Blatt GJ. A Subset of Autism-Associated Genes Regulate the Structural Stability of Neurons. Front Cell Neurosci 2016; 10:263. [PMID: 27909399 PMCID: PMC5112273 DOI: 10.3389/fncel.2016.00263] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/28/2016] [Indexed: 12/15/2022] Open
Abstract
Autism spectrum disorder (ASD) comprises a range of neurological conditions that affect individuals’ ability to communicate and interact with others. People with ASD often exhibit marked qualitative difficulties in social interaction, communication, and behavior. Alterations in neurite arborization and dendritic spine morphology, including size, shape, and number, are hallmarks of almost all neurological conditions, including ASD. As experimental evidence emerges in recent years, it becomes clear that although there is broad heterogeneity of identified autism risk genes, many of them converge into similar cellular pathways, including those regulating neurite outgrowth, synapse formation and spine stability, and synaptic plasticity. These mechanisms together regulate the structural stability of neurons and are vulnerable targets in ASD. In this review, we discuss the current understanding of those autism risk genes that affect the structural connectivity of neurons. We sub-categorize them into (1) cytoskeletal regulators, e.g., motors and small RhoGTPase regulators; (2) adhesion molecules, e.g., cadherins, NCAM, and neurexin superfamily; (3) cell surface receptors, e.g., glutamatergic receptors and receptor tyrosine kinases; (4) signaling molecules, e.g., protein kinases and phosphatases; and (5) synaptic proteins, e.g., vesicle and scaffolding proteins. Although the roles of some of these genes in maintaining neuronal structural stability are well studied, how mutations contribute to the autism phenotype is still largely unknown. Investigating whether and how the neuronal structure and function are affected when these genes are mutated will provide insights toward developing effective interventions aimed at improving the lives of people with autism and their families.
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Affiliation(s)
- Yu-Chih Lin
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Jeannine A Frei
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Michaela B C Kilander
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Wenjuan Shen
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Gene J Blatt
- Laboratory of Autism Neurocircuitry, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
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14
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Chazeau A, Giannone G. Organization and dynamics of the actin cytoskeleton during dendritic spine morphological remodeling. Cell Mol Life Sci 2016; 73:3053-73. [PMID: 27105623 PMCID: PMC11108290 DOI: 10.1007/s00018-016-2214-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/31/2016] [Accepted: 03/31/2016] [Indexed: 12/18/2022]
Abstract
In the central nervous system, most excitatory post-synapses are small subcellular structures called dendritic spines. Their structure and morphological remodeling are tightly coupled to changes in synaptic transmission. The F-actin cytoskeleton is the main driving force of dendritic spine remodeling and sustains synaptic plasticity. It is therefore essential to understand how changes in synaptic transmission can regulate the organization and dynamics of actin binding proteins (ABPs). In this review, we will provide a detailed description of the organization and dynamics of F-actin and ABPs in dendritic spines and will discuss the current models explaining how the actin cytoskeleton sustains both structural and functional synaptic plasticity.
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Affiliation(s)
- Anaël Chazeau
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, UMR 5297, 33000, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS, UMR 5297, 33000, Bordeaux, France
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Grégory Giannone
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, UMR 5297, 33000, Bordeaux, France.
- Interdisciplinary Institute for Neuroscience, CNRS, UMR 5297, 33000, Bordeaux, France.
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15
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nArgBP2 regulates excitatory synapse formation by controlling dendritic spine morphology. Proc Natl Acad Sci U S A 2016; 113:6749-54. [PMID: 27226294 DOI: 10.1073/pnas.1600944113] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Neural Abelson-related gene-binding protein 2 (nArgBP2) was originally identified as a protein that directly interacts with synapse-associated protein 90/postsynaptic density protein 95-associated protein 3 (SAPAP3), a postsynaptic scaffolding protein critical for the assembly of glutamatergic synapses. Although genetic deletion of nArgBP2 in mice leads to manic/bipolar-like behaviors resembling many aspects of symptoms in patients with bipolar disorder, the actual function of nArgBP2 at the synapse is completely unknown. Here, we found that the knockdown (KD) of nArgBP2 by specific small hairpin RNAs (shRNAs) resulted in a dramatic change in dendritic spine morphology. Reintroducing shRNA-resistant nArgBP2 reversed these defects. In particular, nArgBP2 KD impaired spine-synapse formation such that excitatory synapses terminated mostly at dendritic shafts instead of spine heads in spiny neurons, although inhibitory synapse formation was not affected. nArgBP2 KD further caused a marked increase of actin cytoskeleton dynamics in spines, which was associated with increased Wiskott-Aldrich syndrome protein-family verprolin homologous protein 1 (WAVE1)/p21-activated kinase (PAK) phosphorylation and reduced activity of cofilin. These effects of nArgBP2 KD in spines were rescued by inhibiting PAK or activating cofilin combined with sequestration of WAVE. Together, our results suggest that nArgBP2 functions to regulate spine morphogenesis and subsequent spine-synapse formation at glutamatergic synapses. They also raise the possibility that the aberrant regulation of synaptic actin filaments caused by reduced nArgBP2 expression may contribute to the manifestation of the synaptic dysfunction observed in manic/bipolar disorder.
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16
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Hlushchenko I, Koskinen M, Hotulainen P. Dendritic spine actin dynamics in neuronal maturation and synaptic plasticity. Cytoskeleton (Hoboken) 2016; 73:435-41. [PMID: 26849484 DOI: 10.1002/cm.21280] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/27/2016] [Accepted: 01/27/2016] [Indexed: 11/09/2022]
Abstract
The majority of the postsynaptic terminals of excitatory synapses in the central nervous system exist on small bulbous structures on dendrites known as dendritic spines. The actin cytoskeleton is a structural element underlying the proper development and morphology of dendritic spines. Synaptic activity patterns rapidly change actin dynamics, leading to morphological changes in dendritic spines. In this mini-review, we will discuss recent findings on neuronal maturation and synaptic plasticity-induced changes in the dendritic spine actin cytoskeleton. We propose that actin dynamics in dendritic spines decrease through actin filament crosslinking during neuronal maturation. In long-term potentiation, we evaluate the model of fast breakdown of actin filaments through severing and rebuilding through polymerization and later stabilization through crosslinking. We will discuss the role of Ca(2+) in long-term depression, and suggest that actin filaments are dissolved through actin filament severing. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Iryna Hlushchenko
- Neuroscience Center, University of Helsinki, Helsinki, Finland.,Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Mikko Koskinen
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Pirta Hotulainen
- Neuroscience Center, University of Helsinki, Helsinki, Finland. .,Minerva Foundation Institute for Medical Research, Helsinki, Finland.
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17
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Henriques AG, Oliveira JM, Carvalho LP, da Cruz E Silva OAB. Aβ Influences Cytoskeletal Signaling Cascades with Consequences to Alzheimer's Disease. Mol Neurobiol 2014; 52:1391-1407. [PMID: 25344315 DOI: 10.1007/s12035-014-8913-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/28/2014] [Indexed: 01/16/2023]
Abstract
Abnormal signal transduction events can impact upon the cytoskeleton, affecting the actin and microtubule networks with direct relevance to Alzheimer's disease (AD). Cytoskeletal anomalies, in turn, promote atypical neuronal responses, with consequences for cellular organization and function. Neuronal cytoskeletal modifications in AD include neurofibrillary tangles, which result from aggregates of hyperphosphorylated tau protein. The latter is a microtubule (MT)-binding protein, whose abnormal phosphorylation leads to MT instability and consequently provokes irregularities in the neuronal trafficking pathways. Early stages of AD are also characterized by synaptic dysfunction and loss of dendritic spines, which correlate with cognitive deficit and impaired brain function. Actin dynamics has a prominent role in maintaining spine plasticity and integrity, thus providing the basis for memory and learning processes. Hence, factors that disrupt both actin and MT network dynamics will compromise neuronal function and survival. The peptide Aβ is the major component of senile plaques and has been described as a pivotal mediator of neuronal dystrophy and synaptic loss in AD. Here, we review Aβ-mediated effects on both MT and actin networks and focus on the relevance of the elicited cytoskeletal signaling events targeted in AD pathology.
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Affiliation(s)
- Ana Gabriela Henriques
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Joana Machado Oliveira
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Liliana Patrícia Carvalho
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, 3810-193, Aveiro, Portugal
| | - Odete A B da Cruz E Silva
- Laboratório de Neurociências e Sinalização, Centro de Biologia Celular, SACS, Universidade de Aveiro, 3810-193, Aveiro, Portugal.
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18
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p140Cap regulates memory and synaptic plasticity through Src-mediated and citron-N-mediated actin reorganization. J Neurosci 2014; 34:1542-53. [PMID: 24453341 DOI: 10.1523/jneurosci.2341-13.2014] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A major challenge in the neuroscience field is the identification of molecules and pathways that control synaptic plasticity and memory. Dendritic spines play a pivotal role in these processes, as the major sites of excitatory synapses in neuronal communication. Previous studies have shown that the scaffold protein p140Cap localizes into dendritic spines and that its knockdown negatively modulates spine shape in culture. However, so far, there is no information on its in vivo relevance. By using a knock-out mouse model, we here demonstrate that p140Cap is a key element for both learning and synaptic plasticity. Indeed, p140Cap(-/-) mice are impaired in object recognition test, as well as in LTP and in LTD measurements. The in vivo effects of p140Cap loss are presumably attenuated by noncell-autonomous events, since primary neurons obtained from p140Cap(-/-) mice show a strong reduction in number of mushroom spines and abnormal organization of synapse-associated F-actin. These phenotypes are most likely caused by a local reduction of the inhibitory control of RhoA and of cortactin toward the actin-depolymerizing factor cofilin. These events can be controlled by p140Cap through its capability to directly inhibit the activation of Src kinase and by its binding to the scaffold protein Citron-N. Altogether, our results provide new insight into how protein associated with dynamic microtubules may regulate spine actin organization through interaction with postsynaptic density components.
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19
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Gordon-Weeks PR, Fournier AE. Neuronal cytoskeleton in synaptic plasticity and regeneration. J Neurochem 2013; 129:206-12. [PMID: 24147810 DOI: 10.1111/jnc.12502] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/20/2013] [Accepted: 10/17/2013] [Indexed: 11/26/2022]
Abstract
During development, dynamic changes in the axonal growth cone and dendrite are necessary for exploratory movements underlying initial axo-dendritic contact and ultimately the formation of a functional synapse. In the adult central nervous system, an impressive degree of plasticity is retained through morphological and molecular rearrangements in the pre- and post-synaptic compartments that underlie the strengthening or weakening of synaptic pathways. Plasticity is regulated by the interplay of permissive and inhibitory extracellular cues, which signal through receptors at the synapse to regulate the closure of critical periods of developmental plasticity as well as by acute changes in plasticity in response to experience and activity in the adult. The molecular underpinnings of synaptic plasticity are actively studied and it is clear that the cytoskeleton is a key substrate for many cues that affect plasticity. Many of the cues that restrict synaptic plasticity exhibit residual activity in the injured adult CNS and restrict regenerative growth by targeting the cytoskeleton. Here, we review some of the latest insights into how cytoskeletal remodeling affects neuronal plasticity and discuss how the cytoskeleton is being targeted in an effort to promote plasticity and repair following traumatic injury in the central nervous system.
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Affiliation(s)
- Phillip R Gordon-Weeks
- The MRC Centre for Developmental Neurobiology, New Hunt's House, Guy's Campus, King's College London, London, UK
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20
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Lin WH, Hurley JT, Raines AN, Cheney RE, Webb DJ. Myosin X and its motorless isoform differentially modulate dendritic spine development by regulating trafficking and retention of vasodilator-stimulated phosphoprotein. J Cell Sci 2013; 126:4756-68. [PMID: 23943878 DOI: 10.1242/jcs.132969] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Myosin X (Myo10) is an unconventional myosin with two known isoforms: full-length (FL)-Myo10 that has motor activity, and a recently identified brain-expressed isoform, headless (Hdl)-Myo10, which lacks most of the motor domain. FL-Myo10 is involved in the regulation of filopodia formation in non-neuronal cells; however, the biological function of Hdl-Myo10 remains largely unknown. Here, we show that FL- and Hdl-Myo10 have important, but distinct, roles in the development of dendritic spines and synapses in hippocampal neurons. FL-Myo10 induces formation of dendritic filopodia and modulates filopodia dynamics by trafficking the actin-binding protein vasodilator-stimulated phosphoprotein (VASP) to the tips of filopodia. By contrast, Hdl-Myo10 acts on dendritic spines to enhance spine and synaptic density as well as spine head expansion by increasing the retention of VASP in spines. Thus, this study demonstrates a novel biological function for Hdl-Myo10 and an important new role for both Myo10 isoforms in the development of dendritic spines and synapses.
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Affiliation(s)
- Wan-Hsin Lin
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
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21
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Romero AM, Renau-Piqueras J, Pilar Marin M, Timoneda J, Berciano MT, Lafarga M, Esteban-Pretel G. Chronic alcohol alters dendritic spine development in neurons in primary culture. Neurotox Res 2013; 24:532-48. [PMID: 23820986 DOI: 10.1007/s12640-013-9409-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/07/2013] [Accepted: 06/21/2013] [Indexed: 12/24/2022]
Abstract
Dendritic spines are specialised membrane protrusions of neuronal dendrites that receive the majority of excitatory synaptic inputs. Abnormal changes in their density, size and morphology have been associated with various neurological and psychiatric disorders, including those deriving from drug addiction. Dendritic spine formation, morphology and synaptic functions are governed by the actin cytoskeleton. Previous in vivo studies have shown that ethanol alters the number and morphology of spines, although the mechanisms underlying these alterations remain unknown. It has also been described how chronic ethanol exposure affects the levels, assembly and cellular organisation of the actin cytoskeleton in hippocampal neurons in primary culture. Therefore, we hypothesised that the ethanol-induced alterations in the number and shape of dendritic spines are due to alterations in the mechanisms regulating actin cytoskeleton integrity. The results presented herein show that chronic exposure to moderate levels of alcohol (30 mM) during the first 2 weeks of culture reduces dendritic spine density and alters the proportion of the different morphologies of these structures in hippocampal neurons, which affects the formation of mature spines. Apparently, these effects are associated with an increase in the G-actin/F-actin ratio due to a reduction of the F-actin fraction, leading to changes in the levels of the different factors regulating the organisation of this cytoskeletal component. The data presented herein indicate that these effects occur between weeks 1 and 2 of culture, an important period in dendritic spines development. These changes may be related to the dysfunction in the memory and learning processes present in children prenatally exposed to ethanol.
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Affiliation(s)
- Ana M Romero
- Sección de Biología y Patología Celular, Centro de Investigación, Hospital Universitario ''La Fe'', Avenida Campanar 21, 46009, Valencia, Spain
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22
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Saneyoshi T, Hayashi Y. The Ca2+ and Rho GTPase signaling pathways underlying activity-dependent actin remodeling at dendritic spines. Cytoskeleton (Hoboken) 2012; 69:545-54. [PMID: 22566410 DOI: 10.1002/cm.21037] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 04/17/2012] [Accepted: 04/25/2012] [Indexed: 02/06/2023]
Abstract
Most excitatory synapses reside on small protrusions located on the dendritic shaft of neurons called dendritic spines. Neuronal activity regulates the number and structure of spines in both developing and mature brains. Such morphological changes are mediated by the modification of the actin cytoskeleton, the major structural component of spines. Because the number and size of spines is tightly correlated with the strength of synaptic transmission, the activity-dependent structural remodeling of a spine plays an important role in the modulation of synaptic transmission. The regulation of spine morphogenesis utilizes multiple intracellular signaling pathways that alter the dynamics of actin remodeling. Here, we will review recent studies examining the signaling pathways underlying activity-dependent actin remodeling at excitatory postsynaptic neurons.
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23
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Sharma S, Grintsevich EE, Phillips ML, Reisler E, Gimzewski JK. Atomic force microscopy reveals drebrin induced remodeling of f-actin with subnanometer resolution. NANO LETTERS 2011; 11:825-827. [PMID: 21175132 PMCID: PMC3670797 DOI: 10.1021/nl104159v] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We show by high-resolution atomic force microscopy analysis that drebrin A (a major neuronal actin binding protein) induced F-actin structural and mechanical remodeling involves significant changes in helical twist and filament stiffness (+55% persistence length). These results provide evidence of a unique mechanical role of drebrin in the dendrites, contribute to current molecular-level understanding of the properties of the neuronal cytoskeleton, and reflect the role of biomechanics at the nanoscale, to modulate nanofilament-structure assemblies such as F-actin.
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Affiliation(s)
- Shivani Sharma
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
| | - Elena E. Grintsevich
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Martin L. Phillips
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Molecular Biology Institute, University of California, Los Angeles, California 90095, United States
| | - James K. Gimzewski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
- International Center for Materials Nanoarchitectonics Satellite (MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0047, Japan
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24
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The dynamic cytoskeleton: backbone of dendritic spine plasticity. Curr Opin Neurobiol 2010; 21:175-81. [PMID: 20832290 DOI: 10.1016/j.conb.2010.08.013] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 08/05/2010] [Accepted: 08/15/2010] [Indexed: 01/11/2023]
Abstract
Dendritic spines are small actin-rich protrusions on the surface of dendrites whose morphological and molecular plasticity play key roles in learning and memory. Both the form and function of spines are critically dependent on the actin cytoskeleton. However, new research, using electron microscopy and live-cell super-resolution microscopy indicates that the actin cytoskeleton is more complex and dynamic than originally thought. Also, exciting recent studies from several labs indicate that microtubules, once thought to be restricted to the dendrite shaft, can make excursions into the most distal regions of dendritic spines. Moreover, microtubule invasions of spines appear to be associated with changes in synaptic activity. Thus, it is likely that dynamic interactions between microtubules and actin filaments within dendritic spines play important roles in dendritic spine plasticity.
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