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Ma Y, Yi C, Zhou Y, Wang Z, Zhao Y, Zhu L, Wang J, Gao S, Liu J, Yuan X, Wang Z, Liu B, Fei P. Semantic redundancy-aware implicit neural compression for multidimensional biomedical image data. Commun Biol 2024; 7:1081. [PMID: 39227646 PMCID: PMC11371832 DOI: 10.1038/s42003-024-06788-0] [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: 02/09/2024] [Accepted: 08/27/2024] [Indexed: 09/05/2024] Open
Abstract
The surge in advanced imaging techniques has generated vast biomedical image data with diverse dimensions in space, time and spectrum, posing big challenges to conventional compression techniques in image storage, transmission, and sharing. Here, we propose an intelligent image compression approach with the first-proved semantic redundancy of biomedical data in the implicit neural function domain. This Semantic redundancy based Implicit Neural Compression guided with Saliency map (SINCS) can notably improve the compression efficiency for arbitrary-dimensional image data in terms of compression ratio and fidelity. Moreover, with weight transfer and residual entropy coding strategies, it shows improved compression speed while maintaining high quality. SINCS yields high quality compression with over 2000-fold compression ratio on 2D, 2D-T, 3D, 4D biomedical images of diverse targets ranging from single virus to entire human organs, and ensures reliable downstream tasks, such as object segmentation and quantitative analyses, to be conducted at high efficiency.
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Affiliation(s)
- Yifan Ma
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Chengqiang Yi
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yao Zhou
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhaofei Wang
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yuxuan Zhao
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Lanxin Zhu
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jie Wang
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Shimeng Gao
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jianchao Liu
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xinyue Yuan
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhaoqiang Wang
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Science, University of California, Los Angeles, Los Angeles, 90095, USA
| | - Binbing Liu
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Peng Fei
- School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
- Advanced Biomedical Imaging Facility Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China.
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2
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Zhao Y, Wan J, Li Y. Genetically encoded sensors for in vivo detection of neurochemicals relevant to depression. J Neurochem 2024; 168:1721-1737. [PMID: 38468468 DOI: 10.1111/jnc.16046] [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: 08/05/2023] [Revised: 12/03/2023] [Accepted: 12/29/2023] [Indexed: 03/13/2024]
Abstract
Depressive disorders are a common and debilitating form of mental illness with significant impacts on individuals and society. Despite the high prevalence, the underlying causes and mechanisms of depressive disorders are still poorly understood. Neurochemical systems, including serotonin, norepinephrine, and dopamine, have been implicated in the development and perpetuation of depressive symptoms. Current treatments for depression target these neuromodulator systems, but there is a need for a better understanding of their role in order to develop more effective treatments. Monitoring neurochemical dynamics during depressive symptoms is crucial for gaining a better a understanding of their involvement in depressive disorders. Genetically encoded sensors have emerged recently that offer high spatial-temporal resolution and the ability to monitor neurochemical dynamics in real time. This review explores the neurochemical systems involved in depression and discusses the applications and limitations of current monitoring tools for neurochemical dynamics. It also highlights the potential of genetically encoded sensors for better characterizing neurochemical dynamics in depression-related behaviors. Furthermore, potential improvements to current sensors are discussed in order to meet the requirements of depression research.
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Affiliation(s)
- Yulin Zhao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Jinxia Wan
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- National Biomedical Imaging Center, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Chinese Institute for Brain Research, Beijing, China
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3
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Ma P, Sternson S, Chen Y. The promise and peril of comparing fluorescence lifetime in biology revealed by simulations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.20.572686. [PMID: 38187652 PMCID: PMC10769356 DOI: 10.1101/2023.12.20.572686] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Signaling dynamics are crucial in biological systems, and biosensor-based real-time imaging has revolutionized their analysis. Fluorescence lifetime imaging microscopy (FLIM) excels over the widely used fluorescence intensity imaging by allowing the measurement of absolute signal levels, independent of sensor concentration. This capability enables the comparison of signaling dynamics across different animals, body regions, and timeframes. However, FLIM's advantage can be compromised by factors like autofluorescence in biological experiments. To address this, we introduce FLiSimBA, a flexible computational framework for realistic F luorescence Li fetime Sim ulation for B iological A pplications. Through simulations, we analyze the signal-to-noise ratios of fluorescence lifetime data, determining measurement uncertainty and providing necessary error bars for lifetime measurements. Furthermore, we challenge the belief that fluorescence lifetime is unaffected by sensor expression and establish quantitative limits to this insensitivity in biological applications. Additionally, we propose innovations, notably multiplexed dynamic imaging that combines fluorescence intensity and lifetime measurements. This innovation can transform the number of signals that can be simultaneously monitored, thereby enabling a systems approach in studying signaling dynamics. Thus, by incorporating diverse factors into our simulation framework, we uncover surprises, identify limitations, and propose advancements for fluorescence lifetime imaging in biology. This quantitative framework supports rigorous experimental design, facilitates accurate data interpretation, and paves the way for technological advancements in fluorescence lifetime imaging.
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4
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Barragan EV, Anisimova M, Vijayakumar V, Coblentz A, Park DK, Salaka RJ, Nisan AFK, Petshow S, Dore K, Zito K, Gray JA. d-Serine Inhibits Non-ionotropic NMDA Receptor Signaling. J Neurosci 2024; 44:e0140242024. [PMID: 38942470 PMCID: PMC11308331 DOI: 10.1523/jneurosci.0140-24.2024] [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: 01/17/2024] [Revised: 05/24/2024] [Accepted: 06/25/2024] [Indexed: 06/30/2024] Open
Abstract
NMDA-type glutamate receptors (NMDARs) are widely recognized as master regulators of synaptic plasticity, most notably for driving long-term changes in synapse size and strength that support learning. NMDARs are unique among neurotransmitter receptors in that they require binding of both neurotransmitter (glutamate) and co-agonist (e.g., d-serine) to open the receptor channel, which leads to the influx of calcium ions that drive synaptic plasticity. Over the past decade, evidence has accumulated that NMDARs also support synaptic plasticity via ion flux-independent (non-ionotropic) signaling upon the binding of glutamate in the absence of co-agonist, although conflicting results have led to significant controversy. Here, we hypothesized that a major source of contradictory results might be attributed to variable occupancy of the co-agonist binding site under different experimental conditions. To test this hypothesis, we manipulated co-agonist availability in acute hippocampal slices from mice of both sexes. We found that enzymatic scavenging of endogenous co-agonists enhanced the magnitude of long-term depression (LTD) induced by non-ionotropic NMDAR signaling in the presence of the NMDAR pore blocker MK801. Conversely, a saturating concentration of d-serine completely inhibited LTD and spine shrinkage induced by glutamate binding in the presence of MK801 or Mg2+ Using a Förster resonance energy transfer (FRET)-based assay in cultured neurons, we further found that d-serine completely blocked NMDA-induced conformational movements of the GluN1 cytoplasmic domains in the presence of MK801. Our results support a model in which d-serine availability serves to modulate NMDAR signaling and synaptic plasticity even when the NMDAR is blocked by magnesium.
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Affiliation(s)
- Eden V Barragan
- Center for Neuroscience, University of California, Davis, California 95618
| | - Margarita Anisimova
- Center for Neuroscience, University of California, Davis, California 95618
- Departments of Neurobiology, Physiology and Behavior, University of California, Davis, California 95618
| | - Vishnu Vijayakumar
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, California 92093
| | - Azariah Coblentz
- Center for Neuroscience, University of California, Davis, California 95618
- Departments of Neurobiology, Physiology and Behavior, University of California, Davis, California 95618
| | - Deborah K Park
- Center for Neuroscience, University of California, Davis, California 95618
- Departments of Neurobiology, Physiology and Behavior, University of California, Davis, California 95618
| | - Raghava Jagadeesh Salaka
- Center for Neuroscience, University of California, Davis, California 95618
- Neurology, University of California, Davis, California 95618
| | - Atheer F K Nisan
- Center for Neuroscience, University of California, Davis, California 95618
| | - Samuel Petshow
- Center for Neuroscience, University of California, Davis, California 95618
- Departments of Neurobiology, Physiology and Behavior, University of California, Davis, California 95618
| | - Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, California 92093
| | - Karen Zito
- Center for Neuroscience, University of California, Davis, California 95618
- Departments of Neurobiology, Physiology and Behavior, University of California, Davis, California 95618
| | - John A Gray
- Center for Neuroscience, University of California, Davis, California 95618
- Neurology, University of California, Davis, California 95618
- Psychiatry and Behavioral Sciences, University of California, Davis, California 95618
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5
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Prinkey K, Thompson E, Saikia J, Cid T, Dore K. Fluorescence lifetime imaging of AMPA receptor endocytosis in living neurons: effects of Aβ and PP1. Front Mol Neurosci 2024; 17:1409401. [PMID: 38915938 PMCID: PMC11194458 DOI: 10.3389/fnmol.2024.1409401] [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: 03/29/2024] [Accepted: 05/22/2024] [Indexed: 06/26/2024] Open
Abstract
The relative amount of AMPA receptors expressed at the surface of neurons can be measured using superecliptic pHluorin (SEP) labeling at their N-terminus. However, the high signal variability resulting from protein overexpression in neurons and the low signal observed in intracellular vesicles make quantitative characterization of receptor trafficking difficult. Here, we establish a real-time live-cell assay of AMPAR trafficking based on fluorescence lifetime imaging (FLIM), which allows for simultaneous visualization of both surface and intracellular receptors. Using this assay, we found that elevating amyloid-beta (Aβ) levels leads to a strong increase in intracellular GluA1 and GluA2-containing receptors, indicating that Aβ triggers the endocytosis of these AMPARs. In APP/PS1 Alzheimer's disease model mouse neurons, FLIM revealed strikingly different AMPAR trafficking properties for GluA1- and GluA3-containing receptors, suggesting that chronic Aβ exposure triggered the loss of both surface and intracellular GluA3-containing receptors. Interestingly, overexpression of protein phosphatase 1 (PP1) also resulted in GluA1 endocytosis as well as depressed synaptic transmission, confirming the important role of phosphorylation in regulating AMPAR trafficking. This new approach allows for the quantitative measurement of extracellular pH, small changes in receptor trafficking, as well as simultaneous measurement of surface and internalized AMPARs in living neurons, and could therefore be applied to several different studies in the future.
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Affiliation(s)
| | | | | | | | - Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience, School of Medicine, University of California at San Diego, La Jolla, CA, United States
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6
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Barragan EV, Anisimova M, Vijayakumar V, Coblentz AC, Park DK, Salaka RJ, Nisan AFK, Petshow S, Dore K, Zito K, Gray JA. D-Serine inhibits non-ionotropic NMDA receptor signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.29.596266. [PMID: 38854020 PMCID: PMC11160797 DOI: 10.1101/2024.05.29.596266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
NMDA-type glutamate receptors (NMDARs) are widely recognized as master regulators of synaptic plasticity, most notably for driving long-term changes in synapse size and strength that support learning. NMDARs are unique among neurotransmitter receptors in that they require binding of both neurotransmitter (glutamate) and co-agonist (e.g. d -serine) to open the receptor channel, which leads to the influx of calcium ions that drive synaptic plasticity. Over the past decade, evidence has accumulated that NMDARs also support synaptic plasticity via ion flux-independent (non-ionotropic) signaling upon the binding of glutamate in the absence of co-agonist, although conflicting results have led to significant controversy. Here, we hypothesized that a major source of contradictory results can be attributed to variable occupancy of the co-agonist binding site under different experimental conditions. To test this hypothesis, we manipulated co-agonist availability in acute hippocampal slices from mice of both sexes. We found that enzymatic scavenging of endogenous co-agonists enhanced the magnitude of LTD induced by non-ionotropic NMDAR signaling in the presence of the NMDAR pore blocker, MK801. Conversely, a saturating concentration of d -serine completely inhibited both LTD and spine shrinkage induced by glutamate binding in the presence of MK801. Using a FRET-based assay in cultured neurons, we further found that d -serine completely blocked NMDA-induced conformational movements of the GluN1 cytoplasmic domains in the presence of MK801. Our results support a model in which d -serine inhibits ion flux-independent NMDAR signaling and plasticity, and thus d -serine availability could serve to modulate NMDAR signaling even when the NMDAR is blocked by magnesium. Significance Statement NMDARs are glutamate-gated cation channels that are key regulators of neurodevelopment and synaptic plasticity and unique in their requirement for binding of a co-agonist (e.g. d -serine) in order for the channel to open. NMDARs have been found to drive synaptic plasticity via non-ionotropic (ion flux-independent) signaling upon the binding of glutamate in the absence of co-agonist, though conflicting results have led to controversy. Here, we found that d -serine inhibits non-ionotropic NMDAR-mediated LTD and LTD-associated spine shrinkage. Thus, a major source of the contradictory findings might be attributed to experimental variability in d -serine availability. In addition, the developmental regulation of d -serine levels suggests a role for non-ionotropic NMDAR plasticity during critical periods of plasticity.
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7
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Aeindartehran L, Sadri Z, Rahimi F, Alinejad T. Fluorescence in depth: integration of spectroscopy and imaging with Raman, IR, and CD for advanced research. Methods Appl Fluoresc 2024; 12:032002. [PMID: 38697201 DOI: 10.1088/2050-6120/ad46e6] [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: 12/27/2023] [Accepted: 05/02/2024] [Indexed: 05/04/2024]
Abstract
Fluorescence spectroscopy serves as a vital technique for studying the interaction between light and fluorescent molecules. It encompasses a range of methods, each presenting unique advantages and applications. This technique finds utility in various chemical studies. This review discusses Fluorescence spectroscopy, its branches such as Time-Resolved Fluorescence Spectroscopy (TRFS) and Fluorescence Lifetime Imaging Microscopy (FLIM), and their integration with other spectroscopic methods, including Raman, Infrared (IR), and Circular Dichroism (CD) spectroscopies. By delving into these methods, we aim to provide a comprehensive understanding of the capabilities and significance of fluorescence spectroscopy in scientific research, highlighting its diverse applications and the enhanced understanding it brings when combined with other spectroscopic methods. This review looks at each technique's unique features and applications. It discusses the prospects of their combined use in advancing scientific understanding and applications across various domains.
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Affiliation(s)
- Lida Aeindartehran
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States of America
| | - Zahra Sadri
- Department of Biological Science, Southern Methodist University, Dallas, Texas 75205, United States of America
| | - Fateme Rahimi
- Department of Chemical Engineering, Babol Noshirvani University of Technology, Babol, Iran
| | - Tahereh Alinejad
- The Key Laboratory of Interventional Pulmonology of Zhejiang Province, Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Wenzhou Medical University, South Baixiang, Ouhai District, Wenzhou 325015, Zhejiang, People's Republic of China
- Institute of Cell Growth Factor, Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision, and Brain Health), Wenzhou Medical University, Wenzhou 325000, People's Republic of China
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8
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Mehl BP, Vairaprakash P, Li L, Hinde E, MacNevin CJ, Hsu CW, Gratton E, Liu B, Hahn KM. Live-cell biosensors based on the fluorescence lifetime of environment-sensing dyes. CELL REPORTS METHODS 2024; 4:100734. [PMID: 38503289 PMCID: PMC10985238 DOI: 10.1016/j.crmeth.2024.100734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/13/2023] [Accepted: 02/26/2024] [Indexed: 03/21/2024]
Abstract
In this work, we examine the use of environment-sensitive fluorescent dyes in fluorescence lifetime imaging microscopy (FLIM) biosensors. We screened merocyanine dyes to find an optimal combination of environment-induced lifetime changes, photostability, and brightness at wavelengths suitable for live-cell imaging. FLIM was used to monitor a biosensor reporting conformational changes of endogenous Cdc42 in living cells. The ability to quantify activity using phasor analysis of a single fluorophore (e.g., rather than ratio imaging) eliminated potential artifacts. We leveraged these properties to determine specific concentrations of activated Cdc42 across the cell.
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Affiliation(s)
- Brian P Mehl
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pothiappan Vairaprakash
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Li Li
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Elizabeth Hinde
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California at Irvine, Irvine, CA 92617, USA
| | - Christopher J MacNevin
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Chia-Wen Hsu
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California at Irvine, Irvine, CA 92617, USA
| | - Bei Liu
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Klaus M Hahn
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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9
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Ma P, Chen P, Tilden EI, Aggarwal S, Oldenborg A, Chen Y. Fast and slow: Recording neuromodulator dynamics across both transient and chronic time scales. SCIENCE ADVANCES 2024; 10:eadi0643. [PMID: 38381826 PMCID: PMC10881037 DOI: 10.1126/sciadv.adi0643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 01/17/2024] [Indexed: 02/23/2024]
Abstract
Neuromodulators transform animal behaviors. Recent research has demonstrated the importance of both sustained and transient change in neuromodulators, likely due to tonic and phasic neuromodulator release. However, no method could simultaneously record both types of dynamics. Fluorescence lifetime of optical reporters could offer a solution because it allows high temporal resolution and is impervious to sensor expression differences across chronic periods. Nevertheless, no fluorescence lifetime change across the entire classes of neuromodulator sensors was previously known. Unexpectedly, we find that several intensity-based neuromodulator sensors also exhibit fluorescence lifetime responses. Furthermore, we show that lifetime measures in vivo neuromodulator dynamics both with high temporal resolution and with consistency across animals and time. Thus, we report a method that can simultaneously measure neuromodulator change over transient and chronic time scales, promising to reveal the roles of multi-time scale neuromodulator dynamics in diseases, in response to therapies, and across development and aging.
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Affiliation(s)
- Pingchuan Ma
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
- Ph.D. Program in Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - Peter Chen
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
- Master’s Program in Biomedical Engineering, Washington University, St. Louis, MO 63110, USA
| | - Elizabeth I. Tilden
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
- Ph.D. Program in Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - Samarth Aggarwal
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - Anna Oldenborg
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - Yao Chen
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
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10
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Tilden EI, Maduskar A, Oldenborg A, Sabatini BL, Chen Y. A Cre-dependent reporter mouse for quantitative real-time imaging of protein kinase A activity dynamics. Sci Rep 2024; 14:3054. [PMID: 38321128 PMCID: PMC10847463 DOI: 10.1038/s41598-024-53313-8] [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: 11/17/2023] [Accepted: 01/30/2024] [Indexed: 02/08/2024] Open
Abstract
Intracellular signaling dynamics play a crucial role in cell function. Protein kinase A (PKA) is a key signaling molecule that has diverse functions, from regulating metabolism and brain activity to guiding development and cancer progression. We previously developed an optical reporter, FLIM-AKAR, that allows for quantitative imaging of PKA activity via fluorescence lifetime imaging microscopy and photometry. However, using viral infection or electroporation for the delivery of FLIM-AKAR is invasive and results in variable expression. Here, we developed a reporter mouse, FL-AK, which expresses FLIM-AKAR in a Cre-dependent manner from the ROSA26 locus. FL-AK provides robust and consistent expression of FLIM-AKAR over time. Functionally, the mouse line reports an increase in PKA activity in response to activation of both Gαs and Gαq-coupled receptors in brain slices. In vivo, FL-AK reports PKA phosphorylation in response to neuromodulator receptor activation. Thus, FL-AK provides a quantitative, robust, and flexible method to reveal the dynamics of PKA activity in diverse cell types.
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Affiliation(s)
- Elizabeth I Tilden
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
- Ph.D. Program in Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
| | - Aditi Maduskar
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
| | - Anna Oldenborg
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
| | - Bernardo L Sabatini
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Yao Chen
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA.
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11
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Tilden EI, Maduskar A, Oldenborg A, Sabatini BL, Chen Y. A Cre-dependent reporter mouse for quantitative real-time imaging of Protein Kinase A activity dynamics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.31.565028. [PMID: 37961214 PMCID: PMC10635033 DOI: 10.1101/2023.10.31.565028] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Intracellular signaling dynamics play a crucial role in cell function. Protein kinase A (PKA) is a key signaling molecule that has diverse functions, from regulating metabolism and brain activity to guiding development and cancer progression. We previously developed an optical reporter, FLIM-AKAR, that allows for quantitative imaging of PKA activity via fluorescence lifetime imaging microscopy and photometry. However, using viral infection or electroporation for the delivery of FLIM-AKAR is invasive, cannot easily target sparse or hard-to-transfect/infect cell types, and results in variable expression. Here, we developed a reporter mouse, FL-AK, which expresses FLIM-AKAR in a Cre-dependent manner from the ROSA26 locus. FL-AK provides robust and consistent expression of FLIM-AKAR over time. Functionally, the mouse line reports an increase in PKA activity in response to activation of both Gαs and Gαq-coupled receptors in brain slices. In vivo, FL-AK reports PKA phosphorylation in response to neuromodulator receptor activation. Thus, FL-AK provides a quantitative, robust, and flexible method to reveal the dynamics of PKA activity in diverse cell types.
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Affiliation(s)
- Elizabeth I. Tilden
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, United States
- Ph. D. Program in Neuroscience, Washington University in St. Louis
| | - Aditi Maduskar
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, United States
| | - Anna Oldenborg
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, United States
| | - Bernardo L. Sabatini
- Howard Hughes Medical Institute, Department of Neurobiology, Harvard Medical School, Boston, MA, United States
| | - Yao Chen
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, United States
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12
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Jain A, Nakahata Y, Watabe T, Rusina P, South K, Adachi K, Yan L, Simorowski N, Furukawa H, Yasuda R. Dendritic, delayed, and stochastic CaMKII activation underlies behavioral time scale plasticity in CA1 synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.01.549180. [PMID: 37577549 PMCID: PMC10418109 DOI: 10.1101/2023.08.01.549180] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Behavioral time scale plasticity (BTSP), is a form of non-Hebbian plasticity induced by integrating pre- and postsynaptic components separated by behavioral time scale (seconds). BTSP in the hippocampal CA1 neurons underlies place cell formation. However, the molecular mechanisms underlying this behavioral time scale (eligibility trace) and synapse specificity are unknown. CaMKII can be activated in a synapse-specific manner and remain active for a few seconds, making it a compelling candidate for the eligibility trace during BTSP. Here, we show that BTSP can be induced in a single dendritic spine using 2-photon glutamate uncaging paired with postsynaptic current injection temporally separated by behavioral time scale. Using an improved CaMKII sensor, we saw no detectable CaMKII activation during this BTSP induction. Instead, we observed a dendritic, delayed, and stochastic CaMKII activation (DDSC) associated with Ca 2+ influx and plateau 20-40 s after BTSP induction. DDSC requires both pre-and postsynaptic activity, suggesting that CaMKII can integrate these two signals. Also, optogenetically blocking CaMKII 30 s after the BTSP protocol inhibited synaptic potentiation, indicating that DDSC is an essential mechanism of BTSP. IP3-dependent intracellular Ca 2+ release facilitates both DDSC and BTSP. Thus, our study suggests that the non-synapse specific CaMKII activation provides an instructive signal with an extensive time window over tens of seconds during BTSP.
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13
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Zhang SX, Kim A, Madara JC, Zhu PK, Christenson LF, Lutas A, Kalugin PN, Jin Y, Pal A, Tian L, Lowell BB, Andermann ML. Competition between stochastic neuropeptide signals calibrates the rate of satiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.11.548551. [PMID: 37503012 PMCID: PMC10369917 DOI: 10.1101/2023.07.11.548551] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
We investigated how transmission of hunger- and satiety-promoting neuropeptides, NPY and αMSH, is integrated at the level of intracellular signaling to control feeding. Receptors for these peptides use the second messenger cAMP, but the messenger's spatiotemporal dynamics and role in energy balance are controversial. We show that AgRP axon stimulation in the paraventricular hypothalamus evokes probabilistic and spatially restricted NPY release that triggers stochastic cAMP decrements in downstream MC4R-expressing neurons (PVH MC4R ). Meanwhile, POMC axon stimulation triggers stochastic, αMSH-dependent cAMP increments. NPY and αMSH competitively control cAMP, as reflected by hunger-state-dependent differences in the amplitude and persistence of cAMP transients evoked by each peptide. During feeding bouts, elevated αMSH release and suppressed NPY release cooperatively sustain elevated cAMP in PVH MC4R neurons, thereby potentiating feeding-related excitatory inputs and promoting satiation across minutes. Our findings highlight how state-dependent integration of opposing, quantal peptidergic events by a common biochemical target calibrates energy intake.
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14
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Zheng Y, Li Y. Past, present, and future of tools for dopamine detection. Neuroscience 2023:S0306-4522(23)00295-6. [PMID: 37419404 DOI: 10.1016/j.neuroscience.2023.06.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/09/2023]
Abstract
Dopamine (DA) is a critical neuromodulator involved in various brain functions. To understand how DA regulates neural circuits and behaviors in the physiological and pathological conditions, it is essential to have tools that enable the direct detection of DA dynamics in vivo. Recently, genetically encoded DA sensors based on G protein-coupled receptors revolutionized this field, as it allows us to track in vivo DA dynamic with unprecedented spatial-temporal resolution, high molecular specificity, and sub-second kinetics. In this review, we first summarize traditional DA detection methods. Then we focus on the development of genetically encoded DA sensors and feature its significance to understanding dopaminergic neuromodulation across diverse behaviors and species. Finally, we present our perspectives about the future direction of the next-generation DA sensors and extend their potential applications. Overall, this review offers a comprehensive perspective on the past, present, and future of DA detection tools, with important implications for the study of DA functions in health and disease.
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Affiliation(s)
- Yu Zheng
- Peking-Tsinghua Center for Life Sciences, 100871 Beijing, China
| | - Yulong Li
- Peking-Tsinghua Center for Life Sciences, 100871 Beijing, China; State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, 100871 Beijing, China; PKU-IDG/McGovern Institute for Brain Research, 100871 Beijing, China; National Biomedical Imaging Center, Peking University, 100871 Beijing, China.
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15
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Avivi Kela S, Sethi K, Tan PY, Suresh D, Ong HT, Castaneda PG, Amin MR, Laviv T, Cram EJ, Faix J, Zaidel-Bar R. Tension-dependent RHGF-1 recruitment to stress fibers drives robust spermathecal tissue contraction. J Cell Biol 2022; 222:213784. [PMID: 36574264 PMCID: PMC9798103 DOI: 10.1083/jcb.202203105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 10/03/2022] [Accepted: 11/08/2022] [Indexed: 12/28/2022] Open
Abstract
Contractile epithelial tubes are found in various organs, such as lung airways and blood capillaries. Their ability to sense luminal pressure and respond with adequate contractility is essential for their physiology, and its mis-regulation results in diseases such as asthma and hypertension. Here, we describe a mechanoresponsive regulatory pathway downstream of tissue stretching that controls contraction of the C. elegans spermatheca, a tubular structure where fertilization occurs. Using live-imaging, we show that ovulation-induced stretching of spermathecal cells leads to recruitment of the RhoGEF RHGF-1 to stress fibers, which activates RHO-1 and myosin II in a positive feedback loop. Through deletion analysis, we identified the PDZ domain of RHGF-1 as responsible for F-actin binding, and genetic epistasis analysis with the RhoGAP spv-1 demonstrated that tension-dependent recruitment of RHGF-1 to F-actin is required for robust spermathecal contractility. Our study illustrates how mechanosensitive regulators of Rho GTPases provide epithelial tubes the ability to tune their contractility in response to internal pressure.
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Affiliation(s)
- Shiri Avivi Kela
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Kriti Sethi
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Pei Yi Tan
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Danesha Suresh
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Hui Ting Ong
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | | | - Mustafi R. Amin
- Department of Biology, Northeastern University, Boston, MA, USA
| | - Tal Laviv
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Erin J. Cram
- Department of Biology, Northeastern University, Boston, MA, USA
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Ronen Zaidel-Bar
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel,Correspondence to Ronen Zaidel-Bar:
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16
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Sensitive genetically encoded sensors for population and subcellular imaging of cAMP in vivo. Nat Methods 2022; 19:1461-1471. [PMID: 36303019 PMCID: PMC10171401 DOI: 10.1038/s41592-022-01646-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 09/09/2022] [Indexed: 01/07/2023]
Abstract
Cyclic adenosine monophosphate (cAMP) signaling integrates information from diverse G-protein-coupled receptors, such as neuromodulator receptors, to regulate pivotal biological processes in a cellular-specific and subcellular-specific manner. However, in vivo cellular-resolution imaging of cAMP dynamics remains challenging. Here, we screen existing genetically encoded cAMP sensors and further develop the best performer to derive three improved variants, called cAMPFIREs. Compared with their parental sensor, these sensors exhibit up to 10-fold increased sensitivity to cAMP and a cytosolic distribution. cAMPFIREs are compatible with both ratiometric and fluorescence lifetime imaging and can detect cAMP dynamics elicited by norepinephrine at physiologically relevant, nanomolar concentrations. Imaging of cAMPFIREs in awake mice reveals tonic levels of cAMP in cortical neurons that are associated with wakefulness, modulated by opioids, and differentially regulated across subcellular compartments. Furthermore, enforced locomotion elicits neuron-specific, bidirectional cAMP dynamics. cAMPFIREs also function in Drosophila. Overall, cAMPFIREs may have broad applicability for studying intracellular signaling in vivo.
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17
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Live imaging approach of dynamic multicellular responses in ERK signaling during vertebrate tissue development. Biochem J 2022; 479:129-143. [PMID: 35050327 PMCID: PMC8883488 DOI: 10.1042/bcj20210557] [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: 11/15/2021] [Revised: 12/28/2021] [Accepted: 01/05/2022] [Indexed: 11/17/2022]
Abstract
The chemical and mechanical responses of cells via the exchange of information during growth and development result in the formation of biological tissues. Information processing within the cells through the signaling pathways and networks inherent to the constituent cells has been well-studied. However, the cell signaling mechanisms responsible for generating dynamic multicellular responses in developing tissues remain unclear. Here, I review the dynamic multicellular response systems during the development and growth of vertebrate tissues based on the extracellular signal-regulated kinase (ERK) pathway. First, an overview of the function of the ERK signaling network in cells is provided, followed by descriptions of biosensors essential for live imaging of the quantification of ERK activity in tissues. Then adducing four examples, I highlight the contribution of live imaging techniques for studying the involvement of spatio-temporal patterns of ERK activity change in tissue development and growth. In addition, theoretical implications of ERK signaling are also discussed from the viewpoint of dynamic systems. This review might help in understanding ERK-mediated dynamic multicellular responses and tissue morphogenesis.
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18
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Bessa-Neto D, Beliu G, Kuhlemann A, Pecoraro V, Doose S, Retailleau N, Chevrier N, Perrais D, Sauer M, Choquet D. Bioorthogonal labeling of transmembrane proteins with non-canonical amino acids unveils masked epitopes in live neurons. Nat Commun 2021; 12:6715. [PMID: 34795271 PMCID: PMC8602626 DOI: 10.1038/s41467-021-27025-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 11/01/2021] [Indexed: 12/22/2022] Open
Abstract
Progress in biological imaging is intrinsically linked to advances in labeling methods. The explosion in the development of high-resolution and super-resolution imaging calls for new approaches to label targets with small probes. These should allow to faithfully report the localization of the target within the imaging resolution - typically nowadays a few nanometers - and allow access to any epitope of the target, in the native cellular and tissue environment. We report here the development of a complete labeling and imaging pipeline using genetic code expansion and non-canonical amino acids in neurons that allows to fluorescently label masked epitopes in target transmembrane proteins in live neurons, both in dissociated culture and organotypic brain slices. This allows us to image the differential localization of two AMPA receptor (AMPAR) auxiliary subunits of the transmembrane AMPAR regulatory protein family in complex with their partner with a variety of methods including widefield, confocal, and dSTORM super-resolution microscopy.
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Affiliation(s)
- Diogo Bessa-Neto
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Gerti Beliu
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
- Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
| | - Alexander Kuhlemann
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Valeria Pecoraro
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Sören Doose
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Natacha Retailleau
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Nicolas Chevrier
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - David Perrais
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany.
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France.
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000, Bordeaux, France.
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19
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Massengill CI, Day-Cooney J, Mao T, Zhong H. Genetically encoded sensors towards imaging cAMP and PKA activity in vivo. J Neurosci Methods 2021; 362:109298. [PMID: 34339753 PMCID: PMC8659126 DOI: 10.1016/j.jneumeth.2021.109298] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/22/2021] [Accepted: 07/29/2021] [Indexed: 12/26/2022]
Abstract
Cyclic adenosine monophosphate (cAMP) is a universal second messenger that plays a crucial role in diverse biological functions, ranging from transcription to neuronal plasticity, and from development to learning and memory. In the nervous system, cAMP integrates inputs from many neuromodulators across a wide range of timescales - from seconds to hours - to modulate neuronal excitability and plasticity in brain circuits during different animal behavioral states. cAMP signaling events are both cell-specific and subcellularly compartmentalized. The same stimulus may result in different, sometimes opposite, cAMP dynamics in different cells or subcellular compartments. Additionally, the activity of protein kinase A (PKA), a major cAMP effector, is also spatiotemporally regulated. For these reasons, many laboratories have made great strides toward visualizing the intracellular dynamics of cAMP and PKA. To date, more than 80 genetically encoded sensors, including original and improved variants, have been published. It is starting to become possible to visualize cAMP and PKA signaling events in vivo, which is required to study behaviorally relevant cAMP/PKA signaling mechanisms. Despite significant progress, further developments are needed to enhance the signal-to-noise ratio and practical utility of these sensors. This review summarizes the recent advances and challenges in genetically encoded cAMP and PKA sensors with an emphasis on in vivo imaging in the brain during behavior.
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Affiliation(s)
| | - Julian Day-Cooney
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Tianyi Mao
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Haining Zhong
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
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20
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Jing J, Zhou Y, Wang Y. Dimming the donor to brighten up FRET-based biosensors. Cell Calcium 2021; 99:102474. [PMID: 34543786 DOI: 10.1016/j.ceca.2021.102474] [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: 08/27/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 11/17/2022]
Abstract
The current biosensors based on Förster resonance energy transfer (FRET) lack good anisotrophy-based indicators for detecting rotational changes triggered by analyte-binding. Laskaratou et al. developed a FRET-induced Angular Displacement Evaluation via Dim donor (FADED) tool to expand the existing toolkit. With less bleed-through from a donor with dim fluorescence, the changes in acceptor anisotropy signals of these tools could readily indicate cytosolic calcium dynamics.
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Affiliation(s)
- Ji Jing
- The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer, Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China.
| | - Yubin Zhou
- Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, United States
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
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21
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Shimizu T, Murakoshi H, Matsumoto H, Ichino K, Hattori A, Ueno S, Ishida A, Tajiri N, Hida H. Tension Sensor Based on Fluorescence Resonance Energy Transfer Reveals Fiber Diameter-Dependent Mechanical Factors During Myelination. Front Cell Neurosci 2021; 15:685044. [PMID: 34408628 PMCID: PMC8364977 DOI: 10.3389/fncel.2021.685044] [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: 03/24/2021] [Accepted: 07/13/2021] [Indexed: 11/15/2022] Open
Abstract
Oligodendrocytes (OLs) form a myelin sheath around neuronal axons to increase conduction velocity of action potential. Although both large and small diameter axons are intermingled in the central nervous system (CNS), the number of myelin wrapping is related to the axon diameter, such that the ratio of the diameter of the axon to that of the entire myelinated-axon unit is optimal for each axon, which is required for exerting higher brain functions. This indicates there are unknown axon diameter-dependent factors that control myelination. We tried to investigate physical factors to clarify the mechanisms underlying axon diameter-dependent myelination. To visualize OL-generating forces during myelination, a tension sensor based on fluorescence resonance energy transfer (FRET) was used. Polystyrene nanofibers with varying diameters similar to neuronal axons were prepared to investigate biophysical factors regulating the OL-axon interactions. We found that higher tension was generated at OL processes contacting larger diameter fibers compared with smaller diameter fibers. Additionally, OLs formed longer focal adhesions (FAs) on larger diameter axons and shorter FAs on smaller diameter axons. These results suggest that OLs respond to the fiber diameter and activate mechanotransduction initiated at FAs, which controls their cytoskeletal organization and myelin formation. This study leads to the novel and interesting idea that physical factors are involved in myelin formation in response to axon diameter.
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Affiliation(s)
- Takeshi Shimizu
- Department of Neurophysiology and Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hideji Murakoshi
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki, Japan
| | - Hidetoshi Matsumoto
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Meguro, Japan
| | - Kota Ichino
- Department of Materials Science and Engineering, Tokyo Institute of Technology, Meguro, Japan
| | - Atsunori Hattori
- Department of Neurophysiology and Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Shinya Ueno
- Department of Neurophysiology and Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Akimasa Ishida
- Department of Neurophysiology and Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Naoki Tajiri
- Department of Neurophysiology and Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hideki Hida
- Department of Neurophysiology and Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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22
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Hayashi Y. Molecular mechanism of hippocampal long-term potentiation - Towards multiscale understanding of learning and memory. Neurosci Res 2021; 175:3-15. [PMID: 34375719 DOI: 10.1016/j.neures.2021.08.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 11/16/2022]
Abstract
Long-term potentiation (LTP) of synaptic transmission is considered to be a cellular counterpart of learning and memory. Activation of postsynaptic NMDA type glutamate receptor (NMDA-R) induces trafficking of AMPA type glutamate receptors (AMPA-R) and other proteins to the synapse in sequential fashion. At the same time, the dendritic spine expands for long-term and modulation of actin underlies this (structural LTP or sLTP). How these changes persist despite constant diffusion and turnover of the component proteins have been the central focus of the current LTP research. Signaling triggered by Ca2+-influx via NMDA-R triggers kinase including Ca2+/calmodulin-dependent protein kinase II (CaMKII). CaMKII can sustain longer-term biochemical signaling by forming a reciprocally-activating kinase-effector complex with its substrate proteins including Tiam1, thereby regulating persistence of the downstream signaling. Furthermore, activated CaMKII can condense at the synapse through the mechanism of liquid-liquid phase separation (LLPS). This increases the binding capacity at the synapse, thereby contributing to the maintenance of enlarged protein complexes. It may also serve as the synapse tag, which captures newly synthesized proteins.
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Affiliation(s)
- Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.
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23
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Optogenetic Imaging of Protein Activity Using Two-Photon Fluorescence Lifetime Imaging Microscopy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1293:295-308. [PMID: 33398821 DOI: 10.1007/978-981-15-8763-4_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Spatiotemporal dynamics of cellular proteins, including protein-protein interactions and conformational changes, is essential for understanding cellular functions such as synaptic plasticity, cell motility, and cell division. One of the best ways to understand the mechanisms of signal transduction is to visualize protein activity with high spatiotemporal resolution in living cells within tissues. Optogenetic probes such as fluorescent proteins, in combination with Förster Resonance Energy Transfer (FRET) techniques, enable the measurement of protein-protein interactions and conformational changes in response to signaling events in living cells. Of the various FRET detection systems, two-photon fluorescence lifetime imaging microscopy (2pFLIM) is one of the methods best suited to monitoring FRET in subcellular compartments of living cells located deep within tissues, such as brain slices. This review will introduce the principle of 2pFLIM-FRET and the use of chromoproteins for imaging intracellular protein activities and protein-protein interactions. Also, we will discuss two examples of 2pFLIM-FRET application: imaging actin polymerization in synapses of hippocampal neurons in brain sections and detecting small GTPase Cdc42 activity in astrocytes.
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24
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Keyes J, Mehta S, Zhang J. Strategies for Multiplexed Biosensor Imaging to Study Intracellular Signaling Networks. Methods Mol Biol 2021; 2350:1-20. [PMID: 34331275 PMCID: PMC8580745 DOI: 10.1007/978-1-0716-1593-5_1] [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] [Indexed: 03/16/2023]
Abstract
Signal transduction processes are a necessary component of multicellular life, and their dysregulation is the basis for a host of syndromes and diseases. Thus, it is imperative that we discover the complex details of how signal transduction processes result in specific cellular outcomes. One of the primary mechanisms of regulation over signaling pathways is through spatiotemporal control. However, traditional methods are limited in their ability to reveal such details. To overcome these limitations, researchers have developed a variety of genetically encodable, fluorescent protein-based biosensors to study these dynamic processes in real time in living cells. Due to the complexities and interconnectedness of signaling pathways, it is thus desirable to use multiple biosensors in individual cells to better elucidate the relationships between signaling pathways. However, multiplexed imaging with such biosensors has been historically difficult. Nevertheless, recent developments in designs and multiplexing strategies have led to vast improvements in our capabilities. In this review, we provide perspectives on the recently developed biosensor designs and multiplexing strategies that are available for multiplexed imaging of signal transduction pathways.
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Affiliation(s)
- Jeremiah Keyes
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA.
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25
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Rangarajan ES, Primi MC, Colgan LA, Chinthalapudi K, Yasuda R, Izard T. A distinct talin2 structure directs isoform specificity in cell adhesion. J Biol Chem 2020; 295:12885-12899. [PMID: 32605925 DOI: 10.1074/jbc.ra119.010789] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 06/23/2020] [Indexed: 01/25/2023] Open
Abstract
Integrin receptors regulate normal cellular processes such as signaling, cell migration, adhesion to the extracellular matrix, and leukocyte function. Talin recruitment to the membrane is necessary for its binding to and activation of integrin. Vertebrates have two highly conserved talin homologs that differ in their expression patterns. The F1-F3 FERM subdomains of cytoskeletal proteins resemble a cloverleaf, but in talin1, its F1 subdomain and additional F0 subdomain align more linearly with its F2 and F3 subdomains. Here, we present the talin2 crystal structure, revealing that its F0-F1 di-subdomain displays another unprecedented constellation, whereby the F0-F1-F2 adopts a new cloverleaf-like arrangement. Using multiangle light scattering (MALS), fluorescence lifetime imaging (FLIM), and FRET analyses, we found that substituting the corresponding residues in talin2 that abolish lipid binding in talin1 disrupt the binding of talin to the membrane, focal adhesion formation, and cell spreading. Our results provide the molecular details of the functions of specific talin isoforms in cell adhesion.
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Affiliation(s)
- Erumbi S Rangarajan
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Marina C Primi
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Lesley A Colgan
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida, USA
| | - Krishna Chinthalapudi
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Ryohei Yasuda
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, Florida, USA
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, USA.
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26
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Radić M, Šoštar M, Weber I, Ćetković H, Slade N, Herak Bosnar M. The Subcellular Localization and Oligomerization Preferences of NME1/NME2 upon Radiation-Induced DNA Damage. Int J Mol Sci 2020; 21:ijms21072363. [PMID: 32235358 PMCID: PMC7177722 DOI: 10.3390/ijms21072363] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/20/2020] [Accepted: 03/26/2020] [Indexed: 02/06/2023] Open
Abstract
Nucleoside diphosphate kinases (NDPK/NME/Nm23) are enzymes composed of subunits NME1/NDPK A and NME2/NDPK B, responsible for the maintenance of the cellular (d)NTP pool and involved in other cellular processes, such as metastasis suppression and DNA damage repair. Although eukaryotic NDPKs are active only as hexamers, it is unclear whether other NME functions require the hexameric form, and how the isoenzyme composition varies in different cellular compartments. To examine the effect of DNA damage on intracellular localization of NME1 and NME2 and the composition of NME oligomers in the nucleus and the cytoplasm, we used live-cell imaging and the FRET/FLIM technique. We showed that exogenous NME1 and NME2 proteins co-localize in the cytoplasm of non-irradiated cells, and move simultaneously to the nucleus after gamma irradiation. The FRET/FLIM experiments imply that, after DNA damage, there is a slight shift in the homomer/heteromer balance between the nucleus and the cytoplasm. Collectively, our results indicate that, after irradiation, NME1 and NME2 engage in mutual functions in the nucleus, possibly performing specific functions in their homomeric states. Finally, we demonstrated that fluorophores fused to the N-termini of NME polypeptides produce the largest FRET effect and thus recommend this orientation for use in similar studies.
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Affiliation(s)
- Martina Radić
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (M.R.); (N.S.)
| | - Marko Šoštar
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (M.Š.); (I.W.); (H.Ć.)
| | - Igor Weber
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (M.Š.); (I.W.); (H.Ć.)
| | - Helena Ćetković
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (M.Š.); (I.W.); (H.Ć.)
| | - Neda Slade
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (M.R.); (N.S.)
| | - Maja Herak Bosnar
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (M.R.); (N.S.)
- Correspondence: ; Tel.: +385-1-456-0996
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O'Banion CP, Yasuda R. Fluorescent sensors for neuronal signaling. Curr Opin Neurobiol 2020; 63:31-41. [PMID: 32203701 DOI: 10.1016/j.conb.2020.02.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 01/30/2020] [Accepted: 02/13/2020] [Indexed: 12/14/2022]
Abstract
Dissecting neuronal structure and function in relation to behavior is an immense undertaking. Researchers require imaging tools to study neuronal activity and biochemical signaling in situ in order to study the roles of neuronal and biochemical activity in information processing. A large number of genetically encoded fluorescent biosensors have been reported in the literature over the past few years as there is a push to develop new technology in neuroscience. Here, we review the classes and characteristics of fluorescent biosensors and highlight some considerations that investigators should keep in mind when choosing their tool. In addition, we discuss recent advances in biosensor development.
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Affiliation(s)
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, United States.
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28
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Choi JE, Kim J, Kim J. Capturing activated neurons and synapses. Neurosci Res 2020; 152:25-34. [DOI: 10.1016/j.neures.2019.12.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/12/2022]
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Dore K, Malinow R. Elevated PSD-95 Blocks Ion-flux Independent LTD: A Potential New Role for PSD-95 in Synaptic Plasticity. Neuroscience 2020; 456:43-49. [PMID: 32114099 DOI: 10.1016/j.neuroscience.2020.02.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
Abstract
We recently demonstrated that NMDA receptors (NMDARs) are capable of ion-flux independent signaling through conformational change in the NMDAR intracellular domain resulting in long-term depression of synaptic transmission (LTD). Here we show that PSD-95 overexpression blocks agonist induced conformational movement in the NMDAR intracellular domain as well as LTD that is NMDAR-dependent and ion-flux independent. Interestingly, previous studies indicate that overexpressed PSD-95 does not block NMDAR-dependent LTD. These data support a model where ion-flux independent LTD is predominant in young animals, which have synapses with low amounts of PSD-95, whereas only ion flux dependent LTD occurs at more mature synapses, which have more PSD-95 that would block ion-flux independent LTD. These results may reconcile different findings regarding ion-flux independent LTD.
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Affiliation(s)
- Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, United States.
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, United States
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30
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In Vivo Imaging of the Coupling between Neuronal and CREB Activity in the Mouse Brain. Neuron 2019; 105:799-812.e5. [PMID: 31883788 DOI: 10.1016/j.neuron.2019.11.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 10/16/2019] [Accepted: 11/25/2019] [Indexed: 01/15/2023]
Abstract
Sensory experiences cause long-term modifications of neuronal circuits by modulating activity-dependent transcription programs that are vital for regulation of long-term synaptic plasticity and memory. However, it has not been possible to precisely determine the interaction between neuronal activity patterns and transcription factor activity. Here we present a technique using two-photon fluorescence lifetime imaging (2pFLIM) with new FRET biosensors to chronically image in vivo signaling of CREB, an activity-dependent transcription factor important for synaptic plasticity, at single-cell resolution. Simultaneous imaging of the red-shifted CREB sensor and GCaMP permitted exploration of how experience shapes the interplay between CREB and neuronal activity in the neocortex of awake mice. Dark rearing increased the sensitivity of CREB activity to Ca2+ elevations and prolonged the duration of CREB activation to more than 24 h in the visual cortex. This technique will allow researchers to unravel the transcriptional dynamics underlying experience-dependent plasticity in the brain.
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31
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Jongbloets BC, Ma L, Mao T, Zhong H. Visualizing Protein Kinase A Activity In Head-fixed Behaving Mice Using In Vivo Two-photon Fluorescence Lifetime Imaging Microscopy. J Vis Exp 2019. [PMID: 31233029 DOI: 10.3791/59526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Neuromodulation exerts powerful control over brain function. Dysfunction of neuromodulatory systems results in neurological and psychiatric disorders. Despite their importance, technologies for tracking neuromodulatory events with cellular resolution are just beginning to emerge. Neuromodulators, such as dopamine, norepinephrine, acetylcholine, and serotonin, trigger intracellular signaling events via their respective G protein-coupled receptors to modulate neuronal excitability, synaptic communications, and other neuronal functions, thereby regulating information processing in the neuronal network. The above mentioned neuromodulators converge onto the cAMP/protein kinase A (PKA) pathway. Therefore, in vivo PKA imaging with single-cell resolution was developed as a readout for neuromodulatory events in a manner analogous to calcium imaging for neuronal electrical activities. Herein, a method is presented to visualize PKA activity at the level of individual neurons in the cortex of head-fixed behaving mice. To do so, an improved A-kinase activity reporter (AKAR), called tAKARα, is used, which is based on Förster resonance energy transfer (FRET). This genetically-encoded PKA sensor is introduced into the motor cortex via in utero electroporation (IUE) of DNA plasmids, or stereotaxic injection of adeno-associated virus (AAV). FRET changes are imaged using two-photon fluorescence lifetime imaging microscopy (2pFLIM), which offers advantages over ratiometric FRET measurements for quantifying FRET signal in light-scattering brain tissue. To study PKA activities during enforced locomotion, tAKARα is imaged through a chronic cranial window above the cortex of awake, head-fixed mice, which run or rest on a speed-controlled motorized treadmill. This imaging approach will be applicable to many other brain regions to study corresponding behavior-induced PKA activities and to other FLIM-based sensors for in vivo imaging.
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Affiliation(s)
| | - Lei Ma
- Vollum Institute, Oregon Health & Science University
| | - Tianyi Mao
- Vollum Institute, Oregon Health & Science University
| | - Haining Zhong
- Vollum Institute, Oregon Health & Science University;
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32
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Inoue T. TI Workbench, an integrated software package for electrophysiology and imaging. Microscopy (Oxf) 2018; 67:129-143. [PMID: 29554288 DOI: 10.1093/jmicro/dfy015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 02/23/2018] [Indexed: 11/14/2022] Open
Abstract
TI Workbench is a software package that serves as a control and analysis center for cellular imaging and electrophysiological experiments. It is unique among general-purpose software packages where it integrates the control of cellular imaging and electrophysiological devices, as well as sophisticated data analyses, which provides superior usability in imaging experiments combined with electrophysiology. During the development over the last 20 years, the range of supported image acquisition devices has expanded from cooled charge-coupled device (CCD) cameras to multi-photon microscope systems. In this review, I outline the concept of TI Workbench together with its unique functions and features derived from ideas emerging during daily experiments in my own lab and in those of my collaborators over the last 20 years. TI Workbench includes standard functions required for time-lapse multicolor fluorescence imaging and electrophysiological experiments, in addition to specialized functions such as random-scan or conventional raster-scan two-photon microscopy packages and fluorescence life time imaging (FLIM) utilities. Data analysis modules, e.g. digital data filters for temporal waveforms of time-lapse image data and electrophysiology and for 2-D image data, and fluorescence correlation spectroscopy (FCS) analysis functions, are well integrated with data acquisition functions. A notebook function holds formatted text, graphs, image and movie data altogether, which are linked to the actual data files. TI Workbench uses Igor Pro software as a back-end output for publishing. In addition, TI Workbench imports several different formats of image and electrophysiology data, serving as a general-purpose data analysis software package.
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Affiliation(s)
- Takafumi Inoue
- Department of Life Science and Medical Bioscience, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan
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Ma L, Jongbloets BC, Xiong WH, Melander JB, Qin M, Lameyer TJ, Harrison MF, Zemelman BV, Mao T, Zhong H. A Highly Sensitive A-Kinase Activity Reporter for Imaging Neuromodulatory Events in Awake Mice. Neuron 2018; 99:665-679.e5. [PMID: 30100256 PMCID: PMC6152931 DOI: 10.1016/j.neuron.2018.07.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 06/01/2018] [Accepted: 07/11/2018] [Indexed: 01/01/2023]
Abstract
Neuromodulation imposes powerful control over brain function, and cAMP-dependent protein kinase (PKA) is a central downstream mediator of multiple neuromodulators. Although genetically encoded PKA sensors have been developed, single-cell imaging of PKA activity in living mice has not been established. Here, we used two-photon fluorescence lifetime imaging microscopy (2pFLIM) to visualize genetically encoded PKA sensors in response to the neuromodulators norepinephrine and dopamine. We screened available PKA sensors for 2pFLIM and further developed a variant (named tAKARα) with increased sensitivity and a broadened dynamic range. This sensor allowed detection of PKA activation by norepinephrine at physiologically relevant concentrations and kinetics, and by optogenetically released dopamine. In vivo longitudinal 2pFLIM imaging of tAKARα tracked bidirectional PKA activities in individual neurons in awake mice and revealed neuromodulatory PKA events that were associated with wakefulness, pharmacological manipulation, and locomotion. This new sensor combined with 2pFLIM will enable interrogation of neuromodulation-induced PKA signaling in awake animals. VIDEO ABSTRACT.
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Affiliation(s)
- Lei Ma
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Bart C Jongbloets
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Wei-Hong Xiong
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Joshua B Melander
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Maozhen Qin
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Tess J Lameyer
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Madeleine F Harrison
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712, USA
| | - Boris V Zemelman
- Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tianyi Mao
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Haining Zhong
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA.
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PKCα integrates spatiotemporally distinct Ca 2+ and autocrine BDNF signaling to facilitate synaptic plasticity. Nat Neurosci 2018; 21:1027-1037. [PMID: 30013171 PMCID: PMC6100743 DOI: 10.1038/s41593-018-0184-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 05/29/2018] [Indexed: 11/24/2022]
Abstract
The Protein Kinase C (PKC) enzymes have long been established as critical for synaptic plasticity. However, it is unknown whether Ca2+-dependent PKC isozymes are activated in dendritic spines during plasticity, and if so, how this synaptic activity is encoded by PKC. Here, using newly-developed, isozyme-specific sensors, we demonstrate that classic isozymes are activated to varying degrees and with unique kinetics. PKCα is activated robustly and rapidly in stimulated spines and is the only isozyme required for structural plasticity. This specificity, depends on a PDZ-binding domain present only in PKCα. The activation of PKCα during plasticity requires both NMDAR Ca2+-flux and autocrine BDNF-TrkB signaling, two pathways that differ vastly in their spatiotemporal scales of signaling. Our results suggest that by integrating these signals, PKCα combines a measure of recent, nearby synaptic plasticity with local synaptic input, enabling complex cellular computations such as heterosynaptic facilitation of plasticity necessary for efficient hippocampal-dependent learning.
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35
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Desbois M, Crawley O, Evans PR, Baker ST, Masuho I, Yasuda R, Grill B. PAM forms an atypical SCF ubiquitin ligase complex that ubiquitinates and degrades NMNAT2. J Biol Chem 2018; 293:13897-13909. [PMID: 29997255 DOI: 10.1074/jbc.ra118.002176] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/13/2018] [Indexed: 12/20/2022] Open
Abstract
PHR (PAM/Highwire/RPM-1) proteins are conserved RING E3 ubiquitin ligases that function in developmental processes, such as axon termination and synapse formation, as well as axon degeneration. At present, our understanding of how PHR proteins form ubiquitin ligase complexes remains incomplete. Although genetic studies indicate NMNAT2 is an important mediator of PHR protein function in axon degeneration, it remains unknown how PHR proteins inhibit NMNAT2. Here, we decipher the biochemical basis for how the human PHR protein PAM, also called MYCBP2, forms a noncanonical Skp/Cullin/F-box (SCF) complex that contains the F-box protein FBXO45 and SKP1 but lacks CUL1. We show FBXO45 does not simply function in substrate recognition but is important for assembly of the PAM/FBXO45/SKP1 complex. Interestingly, we demonstrate a novel role for SKP1 as an auxiliary component of the target recognition module that enhances binding of FBXO45 to NMNAT2. Finally, we provide biochemical evidence that PAM polyubiquitinates NMNAT2 and regulates NMNAT2 protein stability and degradation by the proteasome.
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Affiliation(s)
- Muriel Desbois
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
| | - Oliver Crawley
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
| | - Paul R Evans
- the Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Scott T Baker
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
| | - Ikuo Masuho
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
| | - Ryohei Yasuda
- the Max Planck Florida Institute for Neuroscience, Jupiter, Florida 33458
| | - Brock Grill
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458 and
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36
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Zou W, Dong X, Broederdorf TR, Shen A, Kramer DA, Shi R, Liang X, Miller DM, Xiang YK, Yasuda R, Chen B, Shen K. A Dendritic Guidance Receptor Complex Brings Together Distinct Actin Regulators to Drive Efficient F-Actin Assembly and Branching. Dev Cell 2018; 45:362-375.e3. [PMID: 29738713 DOI: 10.1016/j.devcel.2018.04.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 01/26/2018] [Accepted: 04/03/2018] [Indexed: 01/05/2023]
Abstract
Proper morphogenesis of dendrites plays a fundamental role in the establishment of neural circuits. The molecular mechanism by which dendrites grow highly complex branches is not well understood. Here, using the Caenorhabditis elegans PVD neuron, we demonstrate that high-order dendritic branching requires actin polymerization driven by coordinated interactions between two membrane proteins, DMA-1 and HPO-30, with their cytoplasmic interactors, the RacGEF TIAM-1 and the actin nucleation promotion factor WAVE regulatory complex (WRC). The dendrite branching receptor DMA-1 directly binds to the PDZ domain of TIAM-1, while the claudin-like protein HPO-30 directly interacts with the WRC. On dendrites, DMA-1 and HPO-30 form a receptor-associated signaling complex to bring TIAM-1 and the WRC to close proximity, leading to elevated assembly of F-actin needed to drive high-order dendrite branching. The synergistic activation of F-actin assembly by scaffolding distinct actin regulators might represent a general mechanism in promoting complex dendrite arborization.
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Affiliation(s)
- Wei Zou
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China; Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China; Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Xintong Dong
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Timothy R Broederdorf
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Ao Shen
- Department of Pharmacology, University of California, Davis, CA 95616, USA
| | - Daniel A Kramer
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Rebecca Shi
- Neurosciences Program, Stanford University, Stanford, CA 94305, USA
| | - Xing Liang
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - David M Miller
- Department of Cell and Developmental Biology and Program in Neuroscience, Vanderbilt University, Nashville, TN 37232, USA
| | - Yang K Xiang
- Department of Pharmacology, University of California, Davis, CA 95616, USA; VA Northern California Health Care System, Mather, CA 95655, USA
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
| | - Kang Shen
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA 94305, USA; National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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37
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Unconventional NMDA Receptor Signaling. J Neurosci 2017; 37:10800-10807. [PMID: 29118208 DOI: 10.1523/jneurosci.1825-17.2017] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/28/2017] [Accepted: 09/28/2017] [Indexed: 11/21/2022] Open
Abstract
In the classical view, NMDA receptors (NMDARs) are stably expressed at the postsynaptic membrane, where they act via Ca2+ to signal coincidence detection in Hebbian plasticity. More recently, it has been established that NMDAR-mediated transmission can be dynamically regulated by neural activity. In addition, NMDARs have been found presynaptically, where they cannot act as conventional coincidence detectors. Unexpectedly, NMDARs have also been shown to signal metabotropically, without the need for Ca2+ This review highlights novel findings concerning these unconventional modes of NMDAR action.
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Endogenous Gαq-Coupled Neuromodulator Receptors Activate Protein Kinase A. Neuron 2017; 96:1070-1083.e5. [PMID: 29154125 DOI: 10.1016/j.neuron.2017.10.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 09/11/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023]
Abstract
Protein kinase A (PKA) integrates inputs from G-protein-coupled neuromodulator receptors to modulate synaptic and cellular function. Gαs signaling stimulates PKA activity, whereas Gαi inhibits PKA activity. Gαq, on the other hand, signals through phospholipase C, and it remains unclear whether Gαq-coupled receptors signal to PKA in their native context. Here, using two independent optical reporters of PKA activity in acute mouse hippocampus slices, we show that endogenous Gαq-coupled muscarinic acetylcholine receptors activate PKA. Mechanistically, this effect is mediated by parallel signaling via either calcium or protein kinase C. Furthermore, multiple Gαq-coupled receptors modulate phosphorylation by PKA, a classical Gαs/Gαi effector. Thus, these results highlight PKA as a biochemical integrator of three major types of GPCRs and necessitate reconsideration of classic models used to predict neuronal signaling in response to the large family of Gαq-coupled receptors.
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Zoltowska KM, Maesako M, Lushnikova I, Takeda S, Keller LJ, Skibo G, Hyman BT, Berezovska O. Dynamic presenilin 1 and synaptotagmin 1 interaction modulates exocytosis and amyloid β production. Mol Neurodegener 2017; 12:15. [PMID: 28193235 PMCID: PMC5307796 DOI: 10.1186/s13024-017-0159-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 02/09/2017] [Indexed: 01/09/2023] Open
Abstract
Background Alzheimer’s disease (AD)-linked protein, presenilin 1 (PS1), is present at the synapse, and the knock-out of presenilin in mice leads to synaptic dysfunction. On the other hand, synaptic activity was shown to influence PS1-dependent generation of distinct amyloid β (Aβ) species. However, the precise nature of these regulations remains unclear. The current study reveals novel role of PS1 at the synapse, and deciphers how PS1 and synaptic vesicle-associated protein, synaptotagmin 1 (Syt1) modulate each other functions in neurons via direct activity-triggered interaction. Additionally, the therapeutic potential of fostering PS1-Syt1 binding is investigated as a synapse-specific strategy for AD prevention. Methods PS1-based cell-permeable peptide targeting PS1-Syt1 binding site was designed to inhibit PS1-Syt1 interaction in neurons. PS1 conformation, synaptic vesicle exocytosis and trafficking were assayed by fluorescence lifetime imaging microscopy (FLIM), glutamate release/synaptopHluorin assay, and fluorescence recovery after photobleaching, respectively. Syt1 level and interaction with PS1 in control and sporadic AD brains were determined by immunohistochemistry and FLIM. AAV-mediated delivery of Syt1 into mouse hippocampi was used to investigate the therapeutic potential of strengthening PS1-Syt1 binding in vivo. Statistical significance was determined using two-tailed unpaired Student’s t-test, Mann-Whitney’s U-test or two-way ANOVA followed by a Bonferroni’s post-test. Results We demonstrate that targeted inhibition of the PS1-Syt1 binding in neurons, without changing the proteins’ expression level, triggers “pathogenic” conformational shift of PS1, and consequent increase in the Aβ42/40 ratio. Moreover, our data indicate that PS1, by binding directly to Syt1, regulates synaptic vesicle trafficking and facilitates exocytosis and neurotransmitter release. Analysis of human brain tissue revealed that not only Syt1 levels but also interactions between remaining Syt1 and PS1 are diminished in sporadic AD. On the other hand, overexpression of Syt1 in mouse hippocampi was found to potentiate PS1-Syt1 binding and promote “protective” PS1 conformation. Conclusions The study reports novel functions of PS1 and Syt1 at the synapse, and demonstrates the importance of PS1-Syt1 binding for exocytosis and safeguarding PS1 conformation. It suggests that reduction in the Syt1 level and PS1-Syt1 interactions in AD brain may present molecular underpinning of the pathogenic PS1 conformation, increased Aβ42/40 ratio, and impaired exocytosis. Electronic supplementary material The online version of this article (doi:10.1186/s13024-017-0159-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katarzyna Marta Zoltowska
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Rm. 2006, 02129, Charlestown, MA, USA
| | - Masato Maesako
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Rm. 2006, 02129, Charlestown, MA, USA
| | - Iryna Lushnikova
- Department of Cytology, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4 Bogomoletz Street, 01024, Kyiv, Ukraine
| | - Shuko Takeda
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Rm. 2006, 02129, Charlestown, MA, USA
| | - Laura J Keller
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Rm. 2006, 02129, Charlestown, MA, USA
| | - Galina Skibo
- Department of Cytology, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4 Bogomoletz Street, 01024, Kyiv, Ukraine
| | - Bradley T Hyman
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Rm. 2006, 02129, Charlestown, MA, USA
| | - Oksana Berezovska
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Rm. 2006, 02129, Charlestown, MA, USA.
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Butz ES, Ben-Johny M, Shen M, Yang PS, Sang L, Biel M, Yue DT, Wahl-Schott C. Quantifying macromolecular interactions in living cells using FRET two-hybrid assays. Nat Protoc 2016; 11:2470-2498. [DOI: 10.1038/nprot.2016.128] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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41
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Hedrick NG, Harward SC, Hall CE, Murakoshi H, McNamara JO, Yasuda R. Rho GTPase complementation underlies BDNF-dependent homo- and heterosynaptic plasticity. Nature 2016; 538:104-108. [PMID: 27680697 DOI: 10.1038/nature19784] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/22/2016] [Indexed: 01/01/2023]
Abstract
The Rho GTPase proteins Rac1, RhoA and Cdc42 have a central role in regulating the actin cytoskeleton in dendritic spines, thereby exerting control over the structural and functional plasticity of spines and, ultimately, learning and memory. Although previous work has shown that precise spatiotemporal coordination of these GTPases is crucial for some forms of cell morphogenesis, the nature of such coordination during structural spine plasticity is unclear. Here we describe a three-molecule model of structural long-term potentiation (sLTP) of murine dendritic spines, implicating the localized, coincident activation of Rac1, RhoA and Cdc42 as a causal signal of sLTP. This model posits that complete tripartite signal overlap in spines confers sLTP, but that partial overlap primes spines for structural plasticity. By monitoring the spatiotemporal activation patterns of these GTPases during sLTP, we find that such spatiotemporal signal complementation simultaneously explains three integral features of plasticity: the facilitation of plasticity by brain-derived neurotrophic factor (BDNF), the postsynaptic source of which activates Cdc42 and Rac1, but not RhoA; heterosynaptic facilitation of sLTP, which is conveyed by diffusive Rac1 and RhoA activity; and input specificity, which is afforded by spine-restricted Cdc42 activity. Thus, we present a form of biochemical computation in dendrites involving the controlled complementation of three molecules that simultaneously ensures signal specificity and primes the system for plasticity.
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Affiliation(s)
- Nathan G Hedrick
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA
| | - Stephen C Harward
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA
| | - Charles E Hall
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA
| | - Hideji Murakoshi
- National Institute for Physiological Science, Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - James O McNamara
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA
| | - Ryohei Yasuda
- Neurobiology Department, Duke University Medical Center, Research Drive, Durham, North Carolina 27710, USA.,Max Planck Florida Institute for Neuroscience, 1 Max Planck Way, Jupiter, Florida 33458, USA
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42
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Autocrine BDNF-TrkB signalling within a single dendritic spine. Nature 2016; 538:99-103. [PMID: 27680698 DOI: 10.1038/nature19766] [Citation(s) in RCA: 226] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 08/15/2016] [Indexed: 12/29/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) and its receptor TrkB are crucial for many forms of neuronal plasticity, including structural long-term potentiation (sLTP), which is a correlate of an animal's learning. However, it is unknown whether BDNF release and TrkB activation occur during sLTP, and if so, when and where. Here, using a fluorescence resonance energy transfer-based sensor for TrkB and two-photon fluorescence lifetime imaging microscopy, we monitor TrkB activity in single dendritic spines of CA1 pyramidal neurons in cultured murine hippocampal slices. In response to sLTP induction, we find fast (onset < 1 min) and sustained (>20 min) activation of TrkB in the stimulated spine that depends on NMDAR (N-methyl-d-aspartate receptor) and CaMKII signalling and on postsynaptically synthesized BDNF. We confirm the presence of postsynaptic BDNF using electron microscopy to localize endogenous BDNF to dendrites and spines of hippocampal CA1 pyramidal neurons. Consistent with these findings, we also show rapid, glutamate-uncaging-evoked, time-locked BDNF release from single dendritic spines using BDNF fused to superecliptic pHluorin. We demonstrate that this postsynaptic BDNF-TrkB signalling pathway is necessary for both structural and functional LTP. Together, these findings reveal a spine-autonomous, autocrine signalling mechanism involving NMDAR-CaMKII-dependent BDNF release from stimulated dendritic spines and subsequent TrkB activation on these same spines that is crucial for structural and functional plasticity.
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43
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Dore K, Aow J, Malinow R. The Emergence of NMDA Receptor Metabotropic Function: Insights from Imaging. Front Synaptic Neurosci 2016; 8:20. [PMID: 27516738 PMCID: PMC4963461 DOI: 10.3389/fnsyn.2016.00020] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/06/2016] [Indexed: 01/19/2023] Open
Abstract
The NMDA receptor (R) participates in many important physiological and pathological processes. For example, its activation is required for both long-term potentiation (LTP) and long-term depression (LTD) of synaptic transmission, cellular models of learning and memory. Furthermore, it may play a role in the actions of amyloid-beta on synapses as well as in the signaling leading to cell death following stroke. Until recently, these processes were thought to be mediated by ion-flux through the receptor. Using a combination of imaging and electrophysiological approaches, ion-flux independent functions of the NMDAR were recently examined. In this review, we will discuss the role of metabotropic NMDAR function in LTD and synaptic dysfunction.
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Affiliation(s)
- Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego San Diego, CA, USA
| | - Jonathan Aow
- Genome Institute of Singapore Singapore, Singapore
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego San Diego, CA, USA
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44
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Chu J, Oh Y, Sens A, Ataie N, Dana H, Macklin JJ, Laviv T, Welf ES, Dean KM, Zhang F, Kim BB, Tang CT, Hu M, Baird MA, Davidson MW, Kay MA, Fiolka R, Yasuda R, Kim DS, Ng HL, Lin MZ. A bright cyan-excitable orange fluorescent protein facilitates dual-emission microscopy and enhances bioluminescence imaging in vivo. Nat Biotechnol 2016; 34:760-7. [PMID: 27240196 PMCID: PMC4942401 DOI: 10.1038/nbt.3550] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 03/22/2016] [Indexed: 02/02/2023]
Abstract
Orange-red fluorescent proteins (FPs) are widely used in biomedical research for multiplexed epifluorescence microscopy with GFP-based probes, but their different excitation requirements make multiplexing with new advanced microscopy methods difficult. Separately, orange-red FPs are useful for deep-tissue imaging in mammals owing to the relative tissue transmissibility of orange-red light, but their dependence on illumination limits their sensitivity as reporters in deep tissues. Here we describe CyOFP1, a bright, engineered, orange-red FP that is excitable by cyan light. We show that CyOFP1 enables single-excitation multiplexed imaging with GFP-based probes in single-photon and two-photon microscopy, including time-lapse imaging in light-sheet systems. CyOFP1 also serves as an efficient acceptor for resonance energy transfer from the highly catalytic blue-emitting luciferase NanoLuc. An optimized fusion of CyOFP1 and NanoLuc, called Antares, functions as a highly sensitive bioluminescent reporter in vivo, producing substantially brighter signals from deep tissues than firefly luciferase and other bioluminescent proteins.
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Affiliation(s)
- Jun Chu
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
| | - Younghee Oh
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Neurobiology, Stanford University, Stanford, California, USA
| | - Alex Sens
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Niloufar Ataie
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Hod Dana
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, USA
| | - John J Macklin
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, USA
| | - Tal Laviv
- Max Planck Florida Institute, Jupiter, Florida, USA
| | - Erik S Welf
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kevin M Dean
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Feijie Zhang
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Benjamin B Kim
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Clement Tran Tang
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Michelle Hu
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Michelle A Baird
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA
| | - Michael W Davidson
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA
| | - Mark A Kay
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Genetics, Stanford University, Stanford, California, USA
| | - Reto Fiolka
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | - Douglas S Kim
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, USA
| | - Ho-Leung Ng
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, USA
- University of Hawaii Cancer Center, Honolulu, Hawaii, USA
| | - Michael Z Lin
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Pediatrics, Stanford University, Stanford, California, USA
- Department of Neurobiology, Stanford University, Stanford, California, USA
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45
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Abstract
Provocative emerging evidence suggests that the N-methyl-d-aspartate (NMDA) receptor can signal in the absence of ion flux through the receptor. This non-ionotropic signaling is thought to be due to agonist-induced conformational changes in the receptor, independently of channel opening. Non-ionotropic NMDA receptor signaling has been proposed to be sufficient to induce synaptic long-term depression (LTD), directly challenging the decades-old model that prolonged low-level calcium influx is required to induce LTD. Here, we briefly review these recent findings, focusing primarily on the potential role of non-ionotropic signaling in NMDA receptor-mediated LTD. Further reports concerning additional roles of non-ionotropic NMDA receptor signaling are also discussed. If validated, this new view of NMDA receptor-mediated signaling will usher in an exciting new era of exploring synapse function and dysfunction.
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Affiliation(s)
- John A Gray
- Center for Neuroscience, University of California, Davis, CA, USA; Department of Neurology, University of California, Davis, CA, USA
| | - Karen Zito
- Center for Neuroscience, University of California, Davis, CA, USA; Department of Neurobiology, Physiology & Behavior, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
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46
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Shisa6 traps AMPA receptors at postsynaptic sites and prevents their desensitization during synaptic activity. Nat Commun 2016; 7:10682. [PMID: 26931375 PMCID: PMC4778035 DOI: 10.1038/ncomms10682] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 01/11/2016] [Indexed: 11/08/2022] Open
Abstract
Trafficking and biophysical properties of AMPA receptors (AMPARs) in the brain depend on interactions with associated proteins. We identify Shisa6, a single transmembrane protein, as a stable and directly interacting bona fide AMPAR auxiliary subunit. Shisa6 is enriched at hippocampal postsynaptic membranes and co-localizes with AMPARs. The Shisa6 C-terminus harbours a PDZ domain ligand that binds to PSD-95, constraining mobility of AMPARs in the plasma membrane and confining them to postsynaptic densities. Shisa6 expressed in HEK293 cells alters GluA1- and GluA2-mediated currents by prolonging decay times and decreasing the extent of AMPAR desensitization, while slowing the rate of recovery from desensitization. Using gene deletion, we show that Shisa6 increases rise and decay times of hippocampal CA1 miniature excitatory postsynaptic currents (mEPSCs). Shisa6-containing AMPARs show prominent sustained currents, indicating protection from full desensitization. Accordingly, Shisa6 prevents synaptically trapped AMPARs from depression at high-frequency synaptic transmission. Auxiliary AMPA receptor subunits can affect gating and surface mobility. Here the authors show that Shisa6 traps AMPA receptors at postsynaptic sites via PSD-95, and keeps them in an activated state in the presence of glutamate, preventing full desensitization and consequently synaptic depression.
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47
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Tønnesen J, Nägerl UV. Dendritic Spines as Tunable Regulators of Synaptic Signals. Front Psychiatry 2016; 7:101. [PMID: 27340393 PMCID: PMC4899469 DOI: 10.3389/fpsyt.2016.00101] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/27/2016] [Indexed: 01/17/2023] Open
Abstract
Neurons are perpetually receiving vast amounts of information in the form of synaptic input from surrounding cells. The majority of input occurs at thousands of dendritic spines, which mediate excitatory synaptic transmission in the brain, and is integrated by the dendritic and somatic compartments of the postsynaptic neuron. The functional role of dendritic spines in shaping biochemical and electrical signals transmitted via synapses has long been intensely studied. Yet, many basic questions remain unanswered, in particular regarding the impact of their nanoscale morphology on electrical signals. Here, we review our current understanding of the structure and function relationship of dendritic spines, focusing on the controversy of electrical compartmentalization and the potential role of spine structural changes in synaptic plasticity.
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Affiliation(s)
- Jan Tønnesen
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Bordeaux, France; CNRS UMR 5297, Bordeaux, France
| | - U Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, Bordeaux, France; CNRS UMR 5297, Bordeaux, France
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48
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Kim K, Lakhanpal G, Lu HE, Khan M, Suzuki A, Hayashi MK, Narayanan R, Luyben TT, Matsuda T, Nagai T, Blanpied TA, Hayashi Y, Okamoto K. A Temporary Gating of Actin Remodeling during Synaptic Plasticity Consists of the Interplay between the Kinase and Structural Functions of CaMKII. Neuron 2015; 87:813-26. [PMID: 26291163 DOI: 10.1016/j.neuron.2015.07.023] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 06/11/2015] [Accepted: 07/17/2015] [Indexed: 12/20/2022]
Abstract
The structural modification of dendritic spines plays a critical role in synaptic plasticity. CaMKII is a pivotal molecule involved in this process through both kinase-dependent and independent structural functions, but the respective contributions of these two functions to the synaptic plasticity remain unclear. We demonstrate that the transient interplay between the kinase and structural functions of CaMKII during the induction of synaptic plasticity temporally gates the activity-dependent modification of the actin cytoskeleton. Inactive CaMKII binds F-actin, thereby limiting access of actin-regulating proteins to F-actin and stabilizing spine structure. CaMKII-activating stimuli trigger dissociation of CaMKII from F-actin through specific autophosphorylation reactions within the F-actin binding region and permits F-actin remodeling by regulatory proteins followed by reassociation and restabilization. Blocking the autophosphorylation impairs both functional and structural plasticity without affecting kinase activity. These results underpin the importance of the interplay between the kinase and structural functions of CaMKII in defining a time window permissive for synaptic plasticity.
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Affiliation(s)
- Karam Kim
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan
| | - Gurpreet Lakhanpal
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
| | - Hsiangmin E Lu
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mustafa Khan
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
| | - Akio Suzuki
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan
| | - Mariko Kato Hayashi
- RIKEN-MIT Neuroscience Research Center, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Radhakrishnan Narayanan
- RIKEN-MIT Neuroscience Research Center, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Thomas T Luyben
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada; Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Tomoki Matsuda
- The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
| | - Takeharu Nagai
- The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Yasunori Hayashi
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan; RIKEN-MIT Neuroscience Research Center, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan; School of Life Science, South China Normal University, Guangzhou 510631, China.
| | - Kenichi Okamoto
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada; RIKEN-MIT Neuroscience Research Center, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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49
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Agonist binding to the NMDA receptor drives movement of its cytoplasmic domain without ion flow. Proc Natl Acad Sci U S A 2015; 112:14705-10. [PMID: 26553997 DOI: 10.1073/pnas.1520023112] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The NMDA receptor (R) plays important roles in brain physiology and pathology as an ion channel. Here we examine the ion flow-independent coupling of agonist to the NMDAR cytoplasmic domain (cd). We measure FRET between fluorescently tagged cytoplasmic domains of GluN1 subunits of NMDARs expressed in neurons. Different neuronal compartments display varying levels of FRET, consistent with different NMDARcd conformations. Agonist binding drives a rapid and transient ion flow-independent reduction in FRET between GluN1 subunits within individual NMDARs. Intracellular infusion of an antibody targeting the GluN1 cytoplasmic domain blocks agonist-driven FRET changes in the absence of ion flow, supporting agonist-driven movement of the NMDARcd. These studies indicate that extracellular ligand binding to the NMDAR can transmit conformational information into the cell in the absence of ion flow.
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50
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Murakoshi H, Shibata ACE, Nakahata Y, Nabekura J. A dark green fluorescent protein as an acceptor for measurement of Förster resonance energy transfer. Sci Rep 2015; 5:15334. [PMID: 26469148 PMCID: PMC4606784 DOI: 10.1038/srep15334] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/23/2015] [Indexed: 01/31/2023] Open
Abstract
Measurement of Förster resonance energy transfer by fluorescence lifetime imaging microscopy (FLIM-FRET) is a powerful method for visualization of intracellular signaling activities such as protein-protein interactions and conformational changes of proteins. Here, we developed a dark green fluorescent protein (ShadowG) that can serve as an acceptor for FLIM-FRET. ShadowG is spectrally similar to monomeric enhanced green fluorescent protein (mEGFP) and has a 120-fold smaller quantum yield. When FRET from mEGFP to ShadowG was measured using an mEGFP-ShadowG tandem construct with 2-photon FLIM-FRET, we observed a strong FRET signal with low cell-to-cell variability. Furthermore, ShadowG was applied to a single-molecule FRET sensor to monitor a conformational change of CaMKII and of the light oxygen voltage (LOV) domain in HeLa cells. These sensors showed reduced cell-to-cell variability of both the basal fluorescence lifetime and response signal. In contrast to mCherry- or dark-YFP-based sensors, our sensor allowed for precise measurement of individual cell responses. When ShadowG was applied to a separate-type Ras FRET sensor, it showed a greater response signal than did the mCherry-based sensor. Furthermore, Ras activation and translocation of its effector ERK2 into the nucleus could be observed simultaneously. Thus, ShadowG is a promising FLIM-FRET acceptor.
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Affiliation(s)
- Hideji Murakoshi
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Akihiro C. E. Shibata
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - Yoshihisa Nakahata
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | - Junichi Nabekura
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
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