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Cuhadar U, Calzado-Reyes L, Pascual-Caro C, Aberra AS, Ritzau-Jost A, Aggarwal A, Ibata K, Podgorski K, Yuzaki M, Geis C, Hallerman S, Hoppa MB, de Juan-Sanz J. Activity-driven synaptic translocation of LGI1 controls excitatory neurotransmission. Cell Rep 2024; 43:114186. [PMID: 38700985 DOI: 10.1016/j.celrep.2024.114186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/14/2023] [Accepted: 04/17/2024] [Indexed: 05/05/2024] Open
Abstract
The fine control of synaptic function requires robust trans-synaptic molecular interactions. However, it remains poorly understood how trans-synaptic bridges change to reflect the functional states of the synapse. Here, we develop optical tools to visualize in firing synapses the molecular behavior of two trans-synaptic proteins, LGI1 and ADAM23, and find that neuronal activity acutely rearranges their abundance at the synaptic cleft. Surprisingly, synaptic LGI1 is primarily not secreted, as described elsewhere, but exo- and endocytosed through its interaction with ADAM23. Activity-driven translocation of LGI1 facilitates the formation of trans-synaptic connections proportionally to the history of activity of the synapse, adjusting excitatory transmission to synaptic firing rates. Accordingly, we find that patient-derived autoantibodies against LGI1 reduce its surface fraction and cause increased glutamate release. Our findings suggest that LGI1 abundance at the synaptic cleft can be acutely remodeled and serves as a critical control point for synaptic function.
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Affiliation(s)
- Ulku Cuhadar
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Lorenzo Calzado-Reyes
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Carlos Pascual-Caro
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Aman S Aberra
- Department of Biology, Dartmouth College, Hanover, NH 03755, USA
| | - Andreas Ritzau-Jost
- Carl-Ludwig-Institute of Physiology, Faculty of Medicine, Leipzig University, 04317 Leipzig, Germany
| | - Abhi Aggarwal
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Keiji Ibata
- Department of Neurophysiology, Keio University, Tokyo 160-8582, Japan
| | | | - Michisuke Yuzaki
- Department of Neurophysiology, Keio University, Tokyo 160-8582, Japan
| | - Christian Geis
- Department of Neurology, Section Translational Neuroimmunology, Jena University Hospital, 07747 Jena, Germany
| | - Stefan Hallerman
- Carl-Ludwig-Institute of Physiology, Faculty of Medicine, Leipzig University, 04317 Leipzig, Germany
| | - Michael B Hoppa
- Department of Biology, Dartmouth College, Hanover, NH 03755, USA
| | - Jaime de Juan-Sanz
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France.
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2
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Qi Z, Yang W, Xue B, Chen T, Lu X, Zhang R, Li Z, Zhao X, Zhang Y, Han F, Kong X, Liu R, Yao X, Jia R, Feng S. ROS-mediated lysosomal membrane permeabilization and autophagy inhibition regulate bleomycin-induced cellular senescence. Autophagy 2024:1-17. [PMID: 38762757 DOI: 10.1080/15548627.2024.2353548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 05/06/2024] [Indexed: 05/20/2024] Open
Abstract
Bleomycin exhibits effective chemotherapeutic activity against multiple types of tumors, and also induces various side effects, such as pulmonary fibrosis and neuronal defects, which limit the clinical application of this drug. Macroautophagy/autophagy has been recently reported to be involved in the functions of bleomycin, and yet the mechanisms of their crosstalk remain insufficiently understood. Here, we demonstrated that reactive oxygen species (ROS) produced during bleomycin activation hampered autophagy flux by inducing lysosomal membrane permeabilization (LMP) and obstructing lysosomal degradation. Exhaustion of ROS with N-acetylcysteine relieved LMP and autophagy defects. Notably, we observed that LMP and autophagy blockage preceded the emergence of cellular senescence during bleomycin treatment. In addition, promoting or inhibiting autophagy-lysosome degradation alleviated or exacerbated the phenotypes of senescence, respectively. This suggests the alternation of autophagy activity is more a regulatory mechanism than a consequence of bleomycin-induced cellular senescence. Taken together, we reveal a specific role of bleomycin-induced ROS in mediating defects of autophagic degradation and further regulating cellular senescence in vitro and in vivo. Our findings, conversely, indicate the autophagy-lysosome degradation pathway as a target for modulating the functions of bleomycin. These provide a new perspective for optimizing bleomycin as a clinically applicable chemotherapeutics devoid of severe side-effects.Abbreviations: AT2 cells: type II alveolar epithelial cells; ATG7: autophagy related 7; bEnd.3: mouse brain microvascular endothelial cells; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; CCL2: C-C motif chemokine ligand 2; CDKN1A: cyclin dependent kinase inhibitor 1A; CDKN2A: cyclin dependent kinase inhibitor 2A; FTH1: ferritin heavy polypeptide 1; γ-H2AX: phosphorylated H2A.X variant histone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HUVEC: human umbilical vein endothelial cells; HT22: hippocampal neuronal cell lines; Il: interleukin; LAMP: lysosomal-associated membrane protein; LMP: lysosome membrane permeabilization; MTORC1: mechanistic target of rapamycin kinase complex 1; NAC: N-acetylcysteine; NCOA4: nuclear receptor coactivator 4; PI3K: phosphoinositide 3-kinase; ROS: reactive oxygen species; RPS6KB/S6K: ribosomal protein S6 kinase; SA-GLB1/β-gal: senescence-associated galactosidase, beta 1; SAHF: senescence-associated heterochromatic foci; SASP: senescence-associated secretory phenotype; SEC62: SEC62 homolog, preprotein translocation; SEP: superecliptic pHluorin; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB.
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Affiliation(s)
- Zhangyang Qi
- Department of Orthopaedics, Qilu Hospital, Shandong University Centre for Orthopaedics, Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Weiqi Yang
- Department of Orthopaedics, Qilu Hospital, Shandong University Centre for Orthopaedics, Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Baibing Xue
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Tingjun Chen
- School of Health and Life Sciences, University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
| | - Xianjie Lu
- The Institute for Tissue Engineering and Regenerative Medicine, Liaocheng University/The Liaocheng People's Hospital, Liaocheng, Shandong, China
| | - Rong Zhang
- Department of Orthopaedics, Qilu Hospital, Shandong University Centre for Orthopaedics, Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Zhichao Li
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Xiaoqing Zhao
- Department of Orthopaedics, Qilu Hospital, Shandong University Centre for Orthopaedics, Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Yang Zhang
- Department of Orthopaedics, Qilu Hospital, Shandong University Centre for Orthopaedics, Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Fabin Han
- The Institute for Tissue Engineering and Regenerative Medicine, Liaocheng University/The Liaocheng People's Hospital, Liaocheng, Shandong, China
| | - Xiaohong Kong
- Department of Orthopaedics, Qilu Hospital, Shandong University Centre for Orthopaedics, Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Ruikang Liu
- Shandong Research Institute of Industrial Technology, Jinan, Shandong, China
| | - Xue Yao
- Department of Orthopaedics, Qilu Hospital, Shandong University Centre for Orthopaedics, Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
- Department of Orthopaedics, International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin Key Laboratory of Spine and Spinal Cord, Tianjin Medical University General Hospital, Tianjin, China
| | - Rui Jia
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Shiqing Feng
- Department of Orthopaedics, Qilu Hospital, Shandong University Centre for Orthopaedics, Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
- Department of Orthopaedics, International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin Key Laboratory of Spine and Spinal Cord, Tianjin Medical University General Hospital, Tianjin, China
- Department of Orthopaedics, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
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Saenz J, Khezerlou E, Aggarwal M, Shaikh A, Ganti N, Herborg F, Pan PY. Parkinson's disease gene, Synaptojanin1, dysregulates the surface maintenance of the dopamine transporter. RESEARCH SQUARE 2024:rs.3.rs-4021466. [PMID: 38559229 PMCID: PMC10980101 DOI: 10.21203/rs.3.rs-4021466/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Missense mutations of PARK20/SYNJ1 (synaptojanin1/Synj1) have been linked to complex forms of familial parkinsonism, however, the molecular and cellular changes associated with dopaminergic dysfunction remains unknown. We now report fast depletion of evoked dopamine (DA) and altered maintenance of the axonal dopamine transporter (DAT) in the Synj1+/- neurons. While Synj1 has been traditionally known to facilitate the endocytosis of synaptic vesicles, we demonstrated that axons of cultured Synj1+/- neurons exhibit an increase of total DAT but a reduction of the surface DAT, which could be exacerbated by neuronal activity. We revealed that the loss of surface DAT is specifically associated with the impaired 5'-phosphatase activity of Synj1 and the hyperactive downstream PI(4,5)P2-PKCβ pathway. Thus, our findings provided important mechanistic insight for Synj1-regulated DAT trafficking integral to dysfunctional DA signaling in early parkinsonism.
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Affiliation(s)
- Jacqueline Saenz
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
- Rutgers Graduate School of Biomedical Sciences, Molecular Biosciences Graduate Program, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Elnaz Khezerlou
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Meha Aggarwal
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Amina Shaikh
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Naga Ganti
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Freja Herborg
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Ping-Yue Pan
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
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Bergeman MH, Hernandez MQ, Diefenderfer J, Drewes JA, Velarde K, Tierney WM, Enow JA, Glenn HL, Rahman MM, Hogue IB. Individual herpes simplex virus 1 (HSV-1) particles exit by exocytosis and accumulate at preferential egress sites. J Virol 2024; 98:e0178523. [PMID: 38193690 PMCID: PMC10883806 DOI: 10.1128/jvi.01785-23] [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: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 01/10/2024] Open
Abstract
The human pathogen herpes simplex virus 1 (HSV-1) produces a lifelong infection in the majority of the world's population. While the generalities of alpha herpesvirus assembly and egress pathways are known, the precise molecular and spatiotemporal details remain unclear. In order to study this aspect of HSV-1 infection, we engineered a recombinant HSV-1 strain expressing a pH-sensitive reporter, gM-pHluorin. Using a variety of fluorescent microscopy modalities, we can detect individual virus particles undergoing intracellular transport and exocytosis at the plasma membrane. We show that particles exit from epithelial cells individually, not bulk release of many particles at once, as has been reported for other viruses. In multiple cell types, HSV-1 particles accumulate over time at the cell periphery and cell-cell contacts. We show that this accumulation effect is the result of individual particles undergoing exocytosis at preferential sites and that these egress sites can contribute to cell-cell spread. We also show that the viral membrane proteins gE, gI, and US9, which have important functions in intracellular transport in neurons, are not required for preferential egress and clustering in non-neuronal cells. Importantly, by comparing HSV-1 to a related alpha herpesvirus, pseudorabies virus, we show that this preferential exocytosis and clustering effect are cell type dependent, not virus dependent. This preferential egress and clustering appear to be the result of the arrangement of the microtubule cytoskeleton, as virus particles co-accumulate at the same cell protrusions as an exogenous plus end-directed kinesin motor.IMPORTANCEAlpha herpesviruses produce lifelong infections in their human and animal hosts. The majority of people in the world are infected with herpes simplex virus 1 (HSV-1), which typically causes recurrent oral or genital lesions. However, HSV-1 can also spread to the central nervous system, causing severe encephalitis, and might also contribute to the development of neurodegenerative diseases. Many of the steps of how these viruses infect and replicate inside host cells are known in depth, but the final step, exiting from the infected cell, is not fully understood. In this study, we engineered a novel variant of HSV-1 that allows us to visualize how individual virus particles exit from infected cells. With this imaging assay, we investigated preferential egress site formation in certain cell types and their contribution to the cell-cell spread of HSV-1.
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Affiliation(s)
- Melissa H. Bergeman
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Michaella Q. Hernandez
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | | | - Jake A. Drewes
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Kimberly Velarde
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Wesley M. Tierney
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Junior A. Enow
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Biodesign Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Honor L. Glenn
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Center for Structural Discovery, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Masmudur M. Rahman
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Biodesign Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Ian B. Hogue
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
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5
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Wang Y, Seki T, Gkoupidenis P, Chen Y, Nagata Y, Bonn M. Aqueous chemimemristor based on proton-permeable graphene membranes. Proc Natl Acad Sci U S A 2024; 121:e2314347121. [PMID: 38300862 PMCID: PMC10861866 DOI: 10.1073/pnas.2314347121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 11/30/2023] [Indexed: 02/03/2024] Open
Abstract
Memristive devices, electrical elements whose resistance depends on the history of applied electrical signals, are leading candidates for future data storage and neuromorphic computing. Memristive devices typically rely on solid-state technology, while aqueous memristive devices are crucial for biology-related applications such as next-generation brain-machine interfaces. Here, we report a simple graphene-based aqueous memristive device with long-term and tunable memory regulated by reversible voltage-induced interfacial acid-base equilibria enabled by selective proton permeation through the graphene. Surface-specific vibrational spectroscopy verifies that the memory of the graphene resistivity arises from the hysteretic proton permeation through the graphene, apparent from the reorganization of interfacial water at the graphene/water interface. The proton permeation alters the surface charge density on the CaF2 substrate of the graphene, affecting graphene's electron mobility, and giving rise to synapse-like resistivity dynamics. The results pave the way for developing experimentally straightforward and conceptually simple aqueous electrolyte-based neuromorphic iontronics using two-dimensional (2D) materials.
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Affiliation(s)
- Yongkang Wang
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing211189, China
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Mainz55128, Germany
| | - Takakazu Seki
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Mainz55128, Germany
| | - Paschalis Gkoupidenis
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Mainz55128, Germany
| | - Yunfei Chen
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing211189, China
| | - Yuki Nagata
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Mainz55128, Germany
| | - Mischa Bonn
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Mainz55128, Germany
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Horikoshi M, Harada K, Tsuno S, Kitaguchi T, Hirai MY, Matsumoto M, Terada S, Tsuboi T. Distinct lactate metabolism between hepatocytes and myotubes revealed by live cell imaging with genetically encoded indicators. Biochem Biophys Res Commun 2024; 694:149416. [PMID: 38147697 DOI: 10.1016/j.bbrc.2023.149416] [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: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 12/28/2023]
Abstract
The process of glycolysis breaks down glycogen stored in muscles, producing lactate through pyruvate to generate energy. Excess lactate is then released into the bloodstream. When lactate reaches the liver, it is converted to glucose, which muscles utilize as a substrate to generate ATP. Although the biochemical study of lactate metabolism in hepatocytes and skeletal muscle cells has been extensive, the spatial and temporal dynamics of this metabolism in live cells are still unknown. We observed the dynamics of metabolism-related molecules in primary cultured hepatocytes and a skeletal muscle cell line upon lactate overload. Our observations revealed an increase in cytoplasmic pyruvate concentration in hepatocytes, which led to glucose release. Skeletal muscle cells exhibited elevated levels of lactate and pyruvate levels in both the cytoplasm and mitochondrial matrix. However, mitochondrial ATP levels remained unaffected, indicating that the increased lactate can be converted to pyruvate but is unlikely to be utilized for ATP production. The findings suggest that excess lactate in skeletal muscle cells is taken up into mitochondria with little contribution to ATP production. Meanwhile, lactate released into the bloodstream can be converted to glucose in hepatocytes for subsequent utilization in skeletal muscle cells.
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Affiliation(s)
- Mina Horikoshi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8654, Japan
| | - Kazuki Harada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan
| | - Saki Tsuno
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan; Dairy Science and Technology Institute, Kyodo Milk Industry Co., Ltd., 20-1 Hirai, Hinode, Tokyo 190-0182, Japan
| | - Tetsuya Kitaguchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
| | - Masami Yokota Hirai
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama-city, Kanagawa, 230-0045, Japan
| | - Mitsuharu Matsumoto
- Dairy Science and Technology Institute, Kyodo Milk Industry Co., Ltd., 20-1 Hirai, Hinode, Tokyo 190-0182, Japan
| | - Shin Terada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan
| | - Takashi Tsuboi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8654, Japan; Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
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7
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Li SA, Meng XY, Zhang YJ, Chen CL, Jiao YX, Zhu YQ, Liu PP, Sun W. Progress in pH-Sensitive sensors: essential tools for organelle pH detection, spotlighting mitochondrion and diverse applications. Front Pharmacol 2024; 14:1339518. [PMID: 38269286 PMCID: PMC10806205 DOI: 10.3389/fphar.2023.1339518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 12/20/2023] [Indexed: 01/26/2024] Open
Abstract
pH-sensitive fluorescent proteins have revolutionized the field of cellular imaging and physiology, offering insight into the dynamic pH changes that underlie fundamental cellular processes. This comprehensive review explores the diverse applications and recent advances in the use of pH-sensitive fluorescent proteins. These remarkable tools enable researchers to visualize and monitor pH variations within subcellular compartments, especially mitochondria, shedding light on organelle-specific pH regulation. They play pivotal roles in visualizing exocytosis and endocytosis events in synaptic transmission, monitoring cell death and apoptosis, and understanding drug effects and disease progression. Recent advancements have led to improved photostability, pH specificity, and subcellular targeting, enhancing their utility. Techniques for multiplexed imaging, three-dimensional visualization, and super-resolution microscopy are expanding the horizon of pH-sensitive protein applications. The future holds promise for their integration into optogenetics and drug discovery. With their ever-evolving capabilities, pH-sensitive fluorescent proteins remain indispensable tools for unravelling cellular dynamics and driving breakthroughs in biological research. This review serves as a comprehensive resource for researchers seeking to harness the potential of pH-sensitive fluorescent proteins.
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Affiliation(s)
- Shu-Ang Li
- Clinical Systems Biology Laboratories, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiao-Yan Meng
- Clinical Systems Biology Laboratories, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Ying-Jie Zhang
- Clinical Systems Biology Laboratories, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Cai-Li Chen
- Department of Immunology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan, China
| | - Yu-Xue Jiao
- Clinical Systems Biology Laboratories, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yong-Qing Zhu
- Clinical Systems Biology Laboratories, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Pei-Pei Liu
- Clinical Systems Biology Laboratories, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Wei Sun
- Department of Burn and Repair Reconstruction, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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8
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Schmitt FJ, Mehmood AS, Tüting C, Phan HT, Reisdorf J, Rieder F, Ghane Golmohamadi F, Verma R, Kastritis PL, Laufer J. Effect of Molecular Dynamics and Internal Water Contact on the Photophysical Properties of Red pH-Sensitive Proteins. Biochemistry 2024; 63:82-93. [PMID: 38085825 DOI: 10.1021/acs.biochem.3c00444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The pH dependence of the absorption and (time-resolved) fluorescence of two red-shifted fluorescent proteins, mCardinal and mNeptune, was investigated. Decay-associated spectra were measured following fluorescence excitation at 470 nm in PBS buffer with a pH that ranged from 5.5 to 8.0. The fluorescence of both proteins shows two different decay components. mCardinal exhibits an increase in the long-lived fluorescence component with acidification from 1.34 ns at pH 8.0 to 1.62 ns at pH 5.5. An additional fast decay component with 0.64 ns at pH 8.0 up to 1.1 ns at pH 5.5 was found to be blue-shifted compared to the long-lived component. The fluorescence lifetime of mNeptune is insensitive to pH. DAS of mCardinal were simulated assuming a coupled two-level system to describe the 1S state of the chromophore within two different conformations of the protein. MD simulations were conducted to correlate the experimentally observed pH-induced change in the lifetime in mCardinal with its molecular properties. While the chromophores of both protein variants are stabilized by the same number of hydrogen bonds, it was found that the chromophore in mCardinal exhibits more water contacts compared to mNeptune. In mCardinal, interaction between the chromophore and Glu-145 is reduced as compared to mNeptune, but interaction with Thr-147 which is Ser-147 in mNeptune is stronger in mCardinal. Therefore, the dynamics of the excited-state proton transfer (ESPT) might be different in mCardinal and mNeptune. The pH dependency of ESPT is suggested as a key mechanism for pH sensitivity.
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Affiliation(s)
- Franz-Josef Schmitt
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | - Amna Shah Mehmood
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | - Christian Tüting
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06120 Halle, Saale, Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle, Saale, Germany
| | - Hoang Trong Phan
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
- INM-Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken, Germany
| | - Judith Reisdorf
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | - Fabian Rieder
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | - Farzin Ghane Golmohamadi
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
| | | | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06120 Halle, Saale, Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, 06120 Halle, Saale, Germany
| | - Jan Laufer
- Institute of Physics, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 3, 06120 Halle, Saale, Germany
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Bergeman MH, Velarde K, Glenn HL, Hogue IB. Herpes Simplex Virus 1 (HSV-1) Uses the Rab6 Post-Golgi Secretory Pathway For Viral Egress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571414. [PMID: 38168379 PMCID: PMC10760111 DOI: 10.1101/2023.12.13.571414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Herpes Simplex Virus 1 (HSV-1) is an alpha herpesvirus that infects a majority of the world population. The mechanisms and cellular host factors involved in the intracellular transport and exocytosis of HSV-1 particles are not fully understood. To elucidate these late steps in the replication cycle, we developed a live-cell fluorescence microscopy assay of HSV-1 virion intracellular trafficking and exocytosis. This method allows us to track individual virus particles, and identify the precise moment and location of particle exocytosis using a pH-sensitive reporter. We show that HSV-1 uses the host Rab6 post-Golgi secretory pathway during egress. The small GTPase, Rab6, binds to nascent secretory vesicles at the trans-Golgi network and regulates vesicle trafficking and exocytosis at the plasma membrane. HSV-1 particles colocalize with Rab6a in the region of the Golgi, cotraffic with Rab6a to the cell periphery, and undergo exocytosis from Rab6a vesicles. Consistent with previous reports, we find that HSV-1 particles accumulate at preferential egress sites in infected cells. The Rab6a secretory pathway mediates this preferential/polarized egress, since Rab6a vesicles accumulate near the plasma membrane similarly in uninfected cells. These data suggest that, following particle envelopment, HSV-1 egress follows a pre-existing cellular secretory pathway to exit infected cells rather than novel, virus-induced mechanisms.
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Affiliation(s)
- Melissa H. Bergeman
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Kimberly Velarde
- School of Life Sciences, Arizona State University, Tempe, Arizona
| | - Honor L. Glenn
- Center for Structural Discovery, Biodesign Institute, Arizona State University
| | - Ian B. Hogue
- ASU-Banner Neurodegenerative Disease Research Center, Arizona State University
- School of Life Sciences, Arizona State University, Tempe, Arizona
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10
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Justs KA, Sempertegui S, Riboul DV, Oliva CD, Durbin RJ, Crill S, Stawarski M, Su C, Renden RB, Fily Y, Macleod GT. Mitochondrial phosphagen kinases support the volatile power demands of motor nerve terminals. J Physiol 2023; 601:5705-5732. [PMID: 37942946 PMCID: PMC10841428 DOI: 10.1113/jp284872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 10/17/2023] [Indexed: 11/10/2023] Open
Abstract
Motor neurons are the longest neurons in the body, with axon terminals separated from the soma by as much as a meter. These terminals are largely autonomous with regard to their bioenergetic metabolism and must burn energy at a high rate to sustain muscle contraction. Here, through computer simulation and drawing on previously published empirical data, we determined that motor neuron terminals in Drosophila larvae experience highly volatile power demands. It might not be surprising then, that we discovered the mitochondria in the motor neuron terminals of both Drosophila and mice to be heavily decorated with phosphagen kinases - a key element in an energy storage and buffering system well-characterized in fast-twitch muscle fibres. Knockdown of arginine kinase 1 (ArgK1) in Drosophila larval motor neurons led to several bioenergetic deficits, including mitochondrial matrix acidification and a faster decline in the cytosol ATP to ADP ratio during axon burst firing. KEY POINTS: Neurons commonly fire in bursts imposing highly volatile demands on the bioenergetic machinery that generates ATP. Using a computational approach, we built profiles of presynaptic power demand at the level of single action potentials, as well as the transition from rest to sustained activity. Phosphagen systems are known to buffer ATP levels in muscles and we demonstrate that phosphagen kinases, which support such phosphagen systems, also localize to mitochondria in motor nerve terminals of fruit flies and mice. By knocking down phosphagen kinases in fruit fly motor nerve terminals, and using fluorescent reporters of the ATP:ADP ratio, lactate, pH and Ca2+ , we demonstrate a role for phosphagen kinases in stabilizing presynaptic ATP levels. These data indicate that the maintenance of phosphagen systems in motor neurons, and not just muscle, could be a beneficial initiative in sustaining musculoskeletal health and performance.
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Affiliation(s)
- Karlis A. Justs
- Integrative Biology and Neuroscience Graduate Program, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Sergio Sempertegui
- Department of Physics, College of Science, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Danielle V. Riboul
- Integrative Biology and Neuroscience Graduate Program, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Carlos D. Oliva
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Ryan J. Durbin
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557
| | - Sarah Crill
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Michal Stawarski
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Chenchen Su
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Robert B. Renden
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, 89557
| | - Yaouen Fily
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Gregory T. Macleod
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458, USA
- Institute for Human Health & Disease Intervention, Florida Atlantic University, Jupiter, FL 33458, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL 33458, USA
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11
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Woodard TK, Rioux DJ, Prosser DC. Actin- and microtubule-based motors contribute to clathrin-independent endocytosis in yeast. Mol Biol Cell 2023; 34:ar117. [PMID: 37647159 PMCID: PMC10846617 DOI: 10.1091/mbc.e23-05-0164] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/14/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023] Open
Abstract
Most eukaryotic cells utilize clathrin-mediated endocytosis as well as multiple clathrin-independent pathways to internalize proteins and membranes. Although clathrin-mediated endocytosis has been studied extensively and many machinery proteins have been identified, clathrin-independent pathways remain poorly characterized by comparison. We previously identified the first known yeast clathrin-independent endocytic pathway, which relies on the actin-modulating GTPase Rho1, the formin Bni1 and unbranched actin filaments, but does not require the clathrin coat or core clathrin machinery proteins. In this study, we sought to better understand clathrin-independent endocytosis in yeast by exploring the role of myosins as actin-based motors, because actin is required for endocytosis in yeast. We find that Myo2, which transports secretory vesicles, organelles and microtubules along actin cables to sites of polarized growth, participates in clathrin-independent endocytosis. Unexpectedly, the ability of Myo2 to transport microtubule plus ends to the cell cortex appears to be required for its role in clathrin-independent endocytosis. In addition, dynein, dynactin, and proteins involved in cortical microtubule capture are also required. Thus, our results suggest that interplay between actin and microtubules contributes to clathrin-independent internalization in yeast.
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Affiliation(s)
| | - Daniel J. Rioux
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284
- Life Sciences, Virginia Commonwealth University, Richmond, VA 23284
| | - Derek C. Prosser
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284
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12
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Kim SR, Eom Y, Lee SH. Comprehensive analysis of sex differences in the function and ultrastructure of hippocampal presynaptic terminals. Neurochem Int 2023; 169:105570. [PMID: 37451344 DOI: 10.1016/j.neuint.2023.105570] [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: 01/25/2023] [Revised: 05/08/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023]
Abstract
Sex differences in the brain, encompassing variations in specific brain structures, size, cognitive function, and synaptic connections, have been identified across numerous species. While previous research has explored sex differences in postsynaptic structures, synaptic plasticity, and hippocampus-dependent functions, the hippocampal presynaptic terminals remain largely uninvestigated. The hippocampus is a critical structure responsible for multiple brain functions. This study examined presynaptic differences in cultured hippocampal neurons derived from male and female mice using a combination of biochemical assays, functional analyses measuring exocytosis and endocytosis of synaptic vesicle proteins, ultrastructural analyses via electron microscopy, and presynaptic Ca2+-specific optical probes. Our findings revealed that female neurons exhibited a higher number of synaptic vesicles at presynaptic terminals compared to male neurons. However, no significant differences were observed in presynaptic protein expression, presynaptic terminal ultrastructure, synaptic vesicle exocytosis and endocytosis, or presynaptic Ca2+ alterations between male and female neurons.
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Affiliation(s)
- Sung Rae Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea; Brain Research Core Facilities of Korea Brain Research Institute (KBRI), Daegu 41068, Republic of Korea.
| | - Yunkyung Eom
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
| | - Sung Hoon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
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13
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Queiroz Zetune Villa Real K, Mougios N, Rehm R, Sograte-Idrissi S, Albert L, Rahimi AM, Maidorn M, Hentze J, Martínez-Carranza M, Hosseini H, Saal KA, Oleksiievets N, Prigge M, Tsukanov R, Stenmark P, Fornasiero EF, Opazo F. A Versatile Synaptotagmin-1 Nanobody Provides Perturbation-Free Live Synaptic Imaging And Low Linkage-Error in Super-Resolution Microscopy. SMALL METHODS 2023; 7:e2300218. [PMID: 37421204 DOI: 10.1002/smtd.202300218] [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: 02/21/2023] [Revised: 06/09/2023] [Indexed: 07/10/2023]
Abstract
Imaging of living synapses has relied for over two decades on the overexpression of synaptic proteins fused to fluorescent reporters. This strategy alters the stoichiometry of synaptic components and ultimately affects synapse physiology. To overcome these limitations, here a nanobody is presented that binds the calcium sensor synaptotagmin-1 (NbSyt1). This nanobody functions as an intrabody (iNbSyt1) in living neurons and is minimally invasive, leaving synaptic transmission almost unaffected, as suggested by the crystal structure of the NbSyt1 bound to Synaptotagmin-1 and by the physiological data. Its single-domain nature enables the generation of protein-based fluorescent reporters, as showcased here by measuring spatially localized presynaptic Ca2+ with a NbSyt1- jGCaMP8 chimera. Moreover, the small size of NbSyt1 makes it ideal for various super-resolution imaging methods. Overall, NbSyt1 is a versatile binder that will enable imaging in cellular and molecular neuroscience with unprecedented precision across multiple spatiotemporal scales.
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Affiliation(s)
- Karine Queiroz Zetune Villa Real
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Nikolaos Mougios
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Ronja Rehm
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Shama Sograte-Idrissi
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - László Albert
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Amir Mohammad Rahimi
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Manuel Maidorn
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Jannik Hentze
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
| | - Markel Martínez-Carranza
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Stockholm, SE-10691, Sweden
| | - Hassan Hosseini
- Research Group Neuromodulatory Networks, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
| | - Kim-Ann Saal
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Nazar Oleksiievets
- III. Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany
| | - Matthias Prigge
- Research Group Neuromodulatory Networks, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39118, Magdeburg, Germany
| | - Roman Tsukanov
- III. Institute of Physics - Biophysics, Georg August University, 37077, Göttingen, Germany
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Stockholm, SE-10691, Sweden
| | - Eugenio F Fornasiero
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Felipe Opazo
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073, Göttingen, Germany
- Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, 37075, Göttingen, Germany
- NanoTag Biotechnologies GmbH, 37079, Göttingen, Germany
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14
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Shen Y, Wen Y, Sposini S, Vishwanath AA, Abdelfattah AS, Schreiter ER, Lemieux MJ, de Juan-Sanz J, Perrais D, Campbell RE. Rational Engineering of an Improved Genetically Encoded pH Sensor Based on Superecliptic pHluorin. ACS Sens 2023; 8:3014-3022. [PMID: 37481776 DOI: 10.1021/acssensors.3c00484] [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] [Indexed: 07/25/2023]
Abstract
Genetically encoded pH sensors based on fluorescent proteins are valuable tools for the imaging of cellular events that are associated with pH changes, such as exocytosis and endocytosis. Superecliptic pHluorin (SEP) is a pH-sensitive green fluorescent protein (GFP) variant widely used for such applications. Here, we report the rational design, development, structure, and applications of Lime, an improved SEP variant with higher fluorescence brightness and greater pH sensitivity. The X-ray crystal structure of Lime supports the mechanistic rationale that guided the introduction of beneficial mutations. Lime provides substantial improvements relative to SEP for imaging of endocytosis and exocytosis. Furthermore, Lime and its variants are advantageous for a broader range of applications including the detection of synaptic release and neuronal voltage changes.
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Affiliation(s)
- Yi Shen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yurong Wen
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
- Center for Microbiome Research of Med-X Institute, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
| | - Silvia Sposini
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, Bordeaux 33076, France
- Department of Metabolism, Digestion and Reproduction, Institute of Reproductive and Developmental Biology, Imperial College London, London SW7 2BX, United Kingdom
| | - Anjali Amrapali Vishwanath
- Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, APHP, Häpital de la Pitié Salpêtrière, Sorbonne Université, 75013 Paris, France
| | - Ahmed S Abdelfattah
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virgina 20147, United States
- Department of Neuroscience, Brown University, Providence, Rhode Island 02906, United States
| | - Eric R Schreiter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virgina 20147, United States
| | - M Joanne Lemieux
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Jaime de Juan-Sanz
- Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, APHP, Häpital de la Pitié Salpêtrière, Sorbonne Université, 75013 Paris, France
| | - David Perrais
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, University of Bordeaux, Bordeaux 33076, France
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
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15
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Bebelman MP, Setiawan IM, Bergkamp ND, van Senten JR, Crudden C, Bebelman JPM, Verweij FJ, van Niel G, Siderius M, Pegtel DM, Smit MJ. Exosomal release of the virus-encoded chemokine receptor US28 contributes to chemokine scavenging. iScience 2023; 26:107412. [PMID: 37575190 PMCID: PMC10415803 DOI: 10.1016/j.isci.2023.107412] [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: 03/04/2023] [Revised: 06/22/2023] [Accepted: 07/14/2023] [Indexed: 08/15/2023] Open
Abstract
The human cytomegalovirus (HCMV)-encoded chemokine receptor US28 contributes to various aspects of the viral life cycle and promotes immune evasion by scavenging chemokines from the microenvironment of HCMV-infected cells. In contrast to the plasma membrane localization of most human chemokine receptors, US28 has a predominant intracellular localization. In this study, we used immunofluorescence and electron microscopy to determine the localization of US28 upon exogenous expression, as well as in HCMV-infected cells. We observed that US28 localizes to late endosomal compartments called multivesicular bodies (MVBs), where it is sorted in intraluminal vesicles. Live-cell total internal reflection fluorescence (TIRF) microscopy revealed that US28-containing MVBs can fuse with the plasma membrane, resulting in the secretion of US28 on exosomes. Exosomal US28 binds the chemokines CX3CL1 and CCL5, and US28-containing exosomes inhibited the CX3CL1-CX3CR1 signaling axis. These findings suggest that exosomal release of US28 contributes to chemokine scavenging and immune evasion by HCMV.
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Affiliation(s)
- Maarten P. Bebelman
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
- Department Pathology, Cancer Center Amsterdam, VU University Medical Center, de Boelelaan 1118, Amsterdam 1081 HZ, the Netherlands
| | - Irfan M. Setiawan
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Nick D. Bergkamp
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Jeffrey R. van Senten
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Caitrin Crudden
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
- Department Pathology, Cancer Center Amsterdam, VU University Medical Center, de Boelelaan 1118, Amsterdam 1081 HZ, the Netherlands
| | - Jan Paul M. Bebelman
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Frederik J. Verweij
- Division of Cell Biology, Neurobiology and Biophysics, Utrecht University, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Guillaume van Niel
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266 Université de Paris, Paris, France
| | - Marco Siderius
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - D. Michiel Pegtel
- Department Pathology, Cancer Center Amsterdam, VU University Medical Center, de Boelelaan 1118, Amsterdam 1081 HZ, the Netherlands
| | - Martine J. Smit
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular and Life Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
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16
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Bergeman MH, Hernandez MQ, Diefenderfer J, Drewes JA, Velarde K, Tierney WM, Enow JA, Glenn HL, Rahman MM, Hogue IB. LIVE-CELL FLUORESCENCE MICROSCOPY OF HSV-1 CELLULAR EGRESS BY EXOCYTOSIS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530373. [PMID: 36909512 PMCID: PMC10002666 DOI: 10.1101/2023.02.27.530373] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
The human pathogen Herpes Simplex Virus 1 (HSV-1) produces a lifelong infection in the majority of the world's population. While the generalities of alpha herpesvirus assembly and egress pathways are known, the precise molecular and spatiotemporal details remain unclear. In order to study this aspect of HSV-1 infection, we engineered a recombinant HSV-1 strain expressing a pH-sensitive reporter, gM-pHluorin. Using a variety of fluorescent microscopy modalities, we can detect individual virus particles undergoing intracellular transport and exocytosis at the plasma membrane. We show that particles exit from epithelial cells individually, not bulk release of many particles at once, as has been reported for other viruses. In multiple cell types, HSV-1 particles accumulate over time at the cell periphery and cell-cell contacts. We show that this accumulation effect is the result of individual particles undergoing exocytosis at preferential sites and that these egress sites can contribute to cell-cell spread. We also show that the viral membrane proteins gE, gI, and US9, which have important functions in intracellular transport in neurons, are not required for preferential egress and clustering in non-neuronal cells. Importantly, by comparing HSV-1 to a related alpha herpesvirus, pseudorabies virus, we show that this preferential exocytosis and clustering effect is cell type-dependent, not virus dependent. This preferential egress and clustering appears to be the result of the arrangement of the microtubule cytoskeleton, as virus particles co-accumulate at the same cell protrusions as an exogenous plus end-directed kinesin motor.
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Affiliation(s)
- Melissa H Bergeman
- ASU-Banner Neurodegenerative Research Center, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Michaella Q Hernandez
- ASU-Banner Neurodegenerative Research Center, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Jenna Diefenderfer
- ASU-Banner Neurodegenerative Research Center, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Jake A Drewes
- ASU-Banner Neurodegenerative Research Center, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Kimberly Velarde
- ASU-Banner Neurodegenerative Research Center, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Wesley M Tierney
- ASU-Banner Neurodegenerative Research Center, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Junior A Enow
- Biodesign Center for Personalized Diagnostics, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Honor L Glenn
- Biodesign Center for Structural Discovery, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Masmudur M Rahman
- Biodesign Center for Structural Discovery, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
| | - Ian B Hogue
- ASU-Banner Neurodegenerative Research Center, Arizona State University, Tempe, Arizona, United States
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States
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17
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Durbin RJ, Heredia DJ, Gould TW, Renden RB. Postsynaptic Calcium Extrusion at the Mouse Neuromuscular Junction Alkalinizes the Synaptic Cleft. J Neurosci 2023; 43:5741-5752. [PMID: 37474311 PMCID: PMC10423045 DOI: 10.1523/jneurosci.0815-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/07/2023] [Accepted: 07/14/2023] [Indexed: 07/22/2023] Open
Abstract
Neurotransmission is shaped by extracellular pH. Alkalization enhances pH-sensitive transmitter release and receptor activation, whereas acidification inhibits these processes and can activate acid-sensitive conductances in the synaptic cleft. Previous work has shown that the synaptic cleft can either acidify because of synaptic vesicular release and/or alkalize because of Ca2+ extrusion by the plasma membrane ATPase (PMCA). The direction of change differs across synapse types. At the mammalian neuromuscular junction (NMJ), the direction and magnitude of pH transients in the synaptic cleft during transmission remain ambiguous. We set out to elucidate the extracellular pH transients that occur at this cholinergic synapse under near-physiological conditions and identify their sources. We monitored pH-dependent changes in the synaptic cleft of the mouse levator auris longus using viral expression of the pseudoratiometric probe pHusion-Ex in the muscle. Using mice from both sexes, a significant and prolonged alkalization occurred when stimulating the connected nerve for 5 s at 50 Hz, which was dependent on postsynaptic intracellular Ca2+ release. Sustained stimulation for a longer duration (20 s at 50 Hz) caused additional prolonged net acidification at the cleft. To investigate the mechanism underlying cleft alkalization, we used muscle-expressed GCaMP3 to monitor the contribution of postsynaptic Ca2+ Activity-induced liberation of intracellular Ca2+ in muscle positively correlated with alkalization of the synaptic cleft, whereas inhibiting PMCA significantly decreased the extent of cleft alkalization. Thus, cholinergic synapses of the mouse NMJ typically alkalize because of cytosolic Ca2+ liberated in muscle during activity, unless under highly strenuous conditions where acidification predominates.SIGNIFICANCE STATEMENT Changes in synaptic cleft pH alter neurotransmission, acting on receptors and channels on both sides of the synapse. Synaptic acidification has been associated with a myriad of diseases in the central and peripheral nervous system. Here, we report that in near-physiological recording conditions the cholinergic neuromuscular junction shows use-dependent bidirectional changes in synaptic cleft pH-immediate alkalinization and a long-lasting acidification under prolonged stimulation. These results provide further insight into physiologically relevant changes at cholinergic synapses that have not been defined previously. Understanding and identifying synaptic pH transients during and after neuronal activity provides insight into short-term synaptic plasticity synapses and may identify therapeutic targets for diseases.
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Affiliation(s)
- Ryan J Durbin
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Dante J Heredia
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Thomas W Gould
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
| | - Robert B Renden
- Integrative Neuroscience Graduate Program, University of Nevada, Reno, Reno, Nevada 89557
- Department of Physiology and Cell Biology, University of Nevada, Reno, School of Medicine, Reno, Nevada 89557
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18
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Liu B, Carlson RJ, Pires IS, Gentili M, Feng E, Hellier Q, Schwartz MA, Blainey PC, Irvine DJ, Hacohen N. Human STING is a proton channel. Science 2023; 381:508-514. [PMID: 37535724 DOI: 10.1126/science.adf8974] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 06/30/2023] [Indexed: 08/05/2023]
Abstract
Proton leakage from organelles is a common signal for noncanonical light chain 3B (LC3B) lipidation and inflammasome activation, processes induced upon stimulator of interferon genes (STING) activation. On the basis of structural analysis, we hypothesized that human STING is a proton channel. Indeed, we found that STING activation induced a pH increase in the Golgi and that STING reconstituted in liposomes enabled transmembrane proton transport. Compound 53 (C53), a STING agonist that binds the putative channel interface, blocked STING-induced proton flux in the Golgi and in liposomes. STING-induced LC3B lipidation and inflammasome activation were also inhibited by C53, suggesting that STING's channel activity is critical for these two processes. Thus, STING's interferon-induction function can be decoupled from its roles in LC3B lipidation and inflammasome activation.
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Affiliation(s)
- Bingxu Liu
- Broad Institute, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- The Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
| | - Rebecca J Carlson
- Broad Institute, Cambridge, MA, USA
- Massachusetts Institute of Technology, Department of Health Sciences and Technology, Cambridge, MA, USA
| | - Ivan S Pires
- The Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
| | | | - Ellie Feng
- Broad Institute, Cambridge, MA, USA
- Massachusetts Institute of Technology, Department of Biological Engineering, Cambridge, MA, USA
| | | | - Marc A Schwartz
- Broad Institute, Cambridge, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Division of Hematology and Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Paul C Blainey
- Broad Institute, Cambridge, MA, USA
- The Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
- Massachusetts Institute of Technology, Department of Biological Engineering, Cambridge, MA, USA
| | - Darrell J Irvine
- The Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
| | - Nir Hacohen
- Broad Institute, Cambridge, MA, USA
- Massachusetts General Hospital Cancer Center, Boston, MA, USA
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19
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Mohylyak I, Bengochea M, Pascual-Caro C, Asfogo N, Fonseca-Topp S, Danda N, Atak ZK, De Waegeneer M, Plaçais PY, Preat T, Aerts S, Corti O, de Juan-Sanz J, Hassan BA. Developmental transcriptional control of mitochondrial homeostasis is required for activity-dependent synaptic connectivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.11.544500. [PMID: 37333418 PMCID: PMC10274921 DOI: 10.1101/2023.06.11.544500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
During neuronal circuit formation, local control of axonal organelles ensures proper synaptic connectivity. Whether this process is genetically encoded is unclear and if so, its developmental regulatory mechanisms remain to be identified. We hypothesized that developmental transcription factors regulate critical parameters of organelle homeostasis that contribute to circuit wiring. We combined cell type-specific transcriptomics with a genetic screen to discover such factors. We identified Telomeric Zinc finger-Associated Protein (TZAP) as a temporal developmental regulator of neuronal mitochondrial homeostasis genes, including Pink1 . In Drosophila , loss of dTzap function during visual circuit development leads to loss of activity-dependent synaptic connectivity, that can be rescued by Pink1 expression. At the cellular level, loss of dTzap/TZAP leads to defects in mitochondrial morphology, attenuated calcium uptake and reduced synaptic vesicle release in fly and mammalian neurons. Our findings highlight developmental transcriptional regulation of mitochondrial homeostasis as a key factor in activity-dependent synaptic connectivity.
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20
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Chang HF, Schirra C, Pattu V, Krause E, Becherer U. Lytic granule exocytosis at immune synapses: lessons from neuronal synapses. Front Immunol 2023; 14:1177670. [PMID: 37275872 PMCID: PMC10233144 DOI: 10.3389/fimmu.2023.1177670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023] Open
Abstract
Regulated exocytosis is a central mechanism of cellular communication. It is not only the basis for neurotransmission and hormone release, but also plays an important role in the immune system for the release of cytokines and cytotoxic molecules. In cytotoxic T lymphocytes (CTLs), the formation of the immunological synapse is required for the delivery of the cytotoxic substances such as granzymes and perforin, which are stored in lytic granules and released via exocytosis. The molecular mechanisms of their fusion with the plasma membrane are only partially understood. In this review, we discuss the molecular players involved in the regulated exocytosis of CTL, highlighting the parallels and differences to neuronal synaptic transmission. Additionally, we examine the strengths and weaknesses of both systems to study exocytosis.
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21
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Cook DC, Ryan TA. GABA BR silencing of nerve terminals. eLife 2023; 12:e83530. [PMID: 37014052 PMCID: PMC10115440 DOI: 10.7554/elife.83530] [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: 09/17/2022] [Accepted: 04/03/2023] [Indexed: 04/05/2023] Open
Abstract
Control of neurotransmission efficacy is central to theories of how the brain computes and stores information. Presynaptic G-protein coupled receptors (GPCRs) are critical in this problem as they locally influence synaptic strength and can operate on a wide range of time scales. Among the mechanisms by which GPCRs impact neurotransmission is by inhibiting voltage-gated calcium (Ca2+) influx in the active zone. Here, using quantitative analysis of both single bouton Ca2+ influx and exocytosis, we uncovered an unexpected non-linear relationship between the magnitude of action potential driven Ca2+ influx and the concentration of external Ca2+ ([Ca2+]e). We find that this unexpected relationship is leveraged by GPCR signaling when operating at the nominal physiological set point for [Ca2+]e, 1.2 mM, to achieve complete silencing of nerve terminals. These data imply that the information throughput in neural circuits can be readily modulated in an all-or-none fashion at the single synapse level when operating at the physiological set point.
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Affiliation(s)
- Daniel C Cook
- Department of Anesthesiology, Weill Cornell Medical CollegeNew YorkUnited States
| | - Timothy A Ryan
- Department of Anesthesiology, Weill Cornell Medical CollegeNew YorkUnited States
- Department of Biochemistry, Weill Cornell Medical CollegeNew YorkUnited States
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22
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Seidenthal M, Jánosi B, Rosenkranz N, Schuh N, Elvers N, Willoughby M, Zhao X, Gottschalk A. pOpsicle: An all-optical reporter system for synaptic vesicle recycling combining pH-sensitive fluorescent proteins with optogenetic manipulation of neuronal activity. Front Cell Neurosci 2023; 17:1120651. [PMID: 37066081 PMCID: PMC10102542 DOI: 10.3389/fncel.2023.1120651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 03/15/2023] [Indexed: 04/03/2023] Open
Abstract
pH-sensitive fluorescent proteins are widely used to study synaptic vesicle (SV) fusion and recycling. When targeted to the lumen of SVs, fluorescence of these proteins is quenched by the acidic pH. Following SV fusion, they are exposed to extracellular neutral pH, resulting in a fluorescence increase. SV fusion, recycling and acidification can thus be tracked by tagging integral SV proteins with pH-sensitive proteins. Neurotransmission is generally activated by electrical stimulation, which is not feasible in small, intact animals. Previous in vivo approaches depended on distinct (sensory) stimuli, thus limiting the addressable neuron types. To overcome these limitations, we established an all-optical approach to stimulate and visualize SV fusion and recycling. We combined distinct pH-sensitive fluorescent proteins (inserted into the SV protein synaptogyrin) and light-gated channelrhodopsins (ChRs) for optical stimulation, overcoming optical crosstalk and thus enabling an all-optical approach. We generated two different variants of the pH-sensitive optogenetic reporter of vesicle recycling (pOpsicle) and tested them in cholinergic neurons of intact Caenorhabditis elegans nematodes. First, we combined the red fluorescent protein pHuji with the blue-light gated ChR2(H134R), and second, the green fluorescent pHluorin combined with the novel red-shifted ChR ChrimsonSA. In both cases, fluorescence increases were observed after optical stimulation. Increase and subsequent decline of fluorescence was affected by mutations of proteins involved in SV fusion and endocytosis. These results establish pOpsicle as a non-invasive, all-optical approach to investigate different steps of the SV cycle.
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Affiliation(s)
- Marius Seidenthal
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Department of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Barbara Jánosi
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Department of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Nils Rosenkranz
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Department of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Noah Schuh
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Department of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Nora Elvers
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Department of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Miles Willoughby
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Department of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Xinda Zhao
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Department of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Department of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
- *Correspondence: Alexander Gottschalk,
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23
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Tang W, Cory B, Lim KL, Fivaz M. The Mood Stabilizer Lithium Slows Down Synaptic Vesicle Cycling at Glutamatergic Synapses. Neuromolecular Med 2023; 25:125-135. [PMID: 36436129 DOI: 10.1007/s12017-022-08729-8] [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: 06/29/2022] [Accepted: 10/31/2022] [Indexed: 11/28/2022]
Abstract
Lithium is a mood stabilizer broadly used to prevent and treat symptoms of mania and depression in people with bipolar disorder (BD). Little is known, however, about its mode of action. Here, we analyzed the impact of lithium on synaptic vesicle (SV) cycling at presynaptic terminals releasing glutamate, a neurotransmitter previously implicated in BD and other neuropsychiatric conditions. We used the pHluorin-based synaptic tracer vGpH and a fully automated image processing pipeline to quantify the effect of lithium on both SV exocytosis and endocytosis in hippocampal neurons. We found that lithium selectively reduces SV exocytic rates during electrical stimulation, and markedly slows down SV recycling post-stimulation. Analysis of single-bouton responses revealed the existence of functionally distinct excitatory synapses with varying sensitivity to lithium-some terminals show responses similar to untreated cells, while others are markedly impaired in their ability to recycle SVs. While the cause of this heterogeneity is unclear, these data indicate that lithium interacts with the SV machinery and influences glutamate release in a large fraction of excitatory synapses. Together, our findings show that lithium down modulates SV cycling, an effect consistent with clinical reports indicating hyperactivation of glutamate neurotransmission in BD.
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Affiliation(s)
- Willcyn Tang
- Department of Research, Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore
- Department of Research, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Bradley Cory
- Stem Cell & Gene Editing Laboratory, Faculty of Science and Engineering, University of Greenwich, Kent, ME4 4TB, UK
| | - Kah-Leong Lim
- Department of Research, Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore.
- Department of Research, National Neuroscience Institute, Singapore, 308433, Singapore.
- Department of Brain Sciences, Imperial College London, London, SW7 2AZ, UK.
| | - Marc Fivaz
- Stem Cell & Gene Editing Laboratory, Faculty of Science and Engineering, University of Greenwich, Kent, ME4 4TB, UK.
- reMYND NV, Bio-Incubator, Gaston Geenslaan 1, Heverlee, 3001, Leuven, Belgium.
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24
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Kim DI, Park S, Ye M, Chen JY, Jhang J, Hunker AC, Zweifel LS, Palmiter RD, Han S. Novel genetically encoded tools for imaging or silencing neuropeptide release from presynaptic terminals in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.19.524797. [PMID: 36712060 PMCID: PMC9882317 DOI: 10.1101/2023.01.19.524797] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Neurons produce and release neuropeptides to communicate with one another. Despite their profound impact on critical brain functions, circuit-based mechanisms of peptidergic transmission are poorly understood, primarily due to the lack of tools for monitoring and manipulating neuropeptide release in vivo. Here, we report the development of two genetically encoded tools for investigating peptidergic transmission in behaving mice: a genetically encoded large dense core vesicle (LDCV) sensor that detects the neuropeptides release presynaptically, and a genetically encoded silencer that specifically degrades neuropeptides inside the LDCV. Monitoring and silencing peptidergic and glutamatergic transmissions from presynaptic terminals using our newly developed tools and existing genetic tools, respectively, reveal that neuropeptides, not glutamate, are the primary transmitter in encoding unconditioned stimulus during Pavlovian threat learning. These results show that our sensor and silencer for peptidergic transmission are reliable tools to investigate neuropeptidergic systems in awake behaving animals.
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Affiliation(s)
- Dong-Il Kim
- Peptide Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Sekun Park
- Howard Hughes Medical Institute, Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Mao Ye
- Peptide Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jane Y. Chen
- Howard Hughes Medical Institute, Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Jinho Jhang
- Peptide Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Avery C. Hunker
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Larry S. Zweifel
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Richard D. Palmiter
- Howard Hughes Medical Institute, Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Sung Han
- Peptide Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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25
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Han S, Bang S, Kim HN, Choi N, Kim SH. Modulating and monitoring the functionality of corticostriatal circuits using an electrostimulable microfluidic device. Mol Brain 2023; 16:13. [PMID: 36670465 PMCID: PMC9863144 DOI: 10.1186/s13041-023-01007-z] [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: 12/08/2022] [Accepted: 01/14/2023] [Indexed: 01/22/2023] Open
Abstract
The central nervous system is organized into different neural circuits, each with particular functions and properties. Studying neural circuits is essential to understanding brain function and neuronal diseases. Microfluidic systems are widely used for reconstructing and studying neural circuits but still need improvement to allow modulation and monitoring of the physiological properties of circuits. In this study, we constructed an improved microfluidic device that supports the electrical modulation of neural circuits and proper reassembly. We demonstrated that our microfluidic device provides a platform for electrically modulating and monitoring the physiological function of neural circuits with genetic indicators for synaptic functionality in corticostriatal (CStr) circuits. In particular, our microfluidic device measures activity-driven Ca2+ dynamics using Ca2+ indicators (synaptophysin-GCaMP6f and Fluo5F-AM), as well as activity-driven synaptic transmission and retrieval using vGlut-pHluorin. Overall, our findings indicate that the improved microfluidic platform described here is an invaluable tool for studying the physiological properties of specific neural circuits.
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Affiliation(s)
- Sukmin Han
- grid.289247.20000 0001 2171 7818Department of Neuroscience, Graduate School, Kyung Hee University, Seoul, 02447 Republic of Korea
| | - Seokyoung Bang
- grid.35541.360000000121053345Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Hong Nam Kim
- grid.35541.360000000121053345Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Nakwon Choi
- grid.35541.360000000121053345Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Sung Hyun Kim
- grid.289247.20000 0001 2171 7818Department of Neuroscience, Graduate School, Kyung Hee University, Seoul, 02447 Republic of Korea ,grid.289247.20000 0001 2171 7818Department of Physiology, School of Medicine, Kyung Hee University, Seoul, 02447 Republic of Korea ,grid.289247.20000 0001 2171 7818Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Kyung Hee University, Seoul, 02447 South Korea
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26
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Hao Y, Toulmé E, König B, Rosenmund C, Plested AJR. Targeted sensors for glutamatergic neurotransmission. eLife 2023; 12:84029. [PMID: 36622100 PMCID: PMC9917459 DOI: 10.7554/elife.84029] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023] Open
Abstract
Optical report of neurotransmitter release allows visualisation of excitatory synaptic transmission. Sensitive genetically-encoded fluorescent glutamate reporters operating with a range of affinities and emission wavelengths are available. However, without targeting to synapses, the specificity of the fluorescent signal is uncertain, compared to sensors directed at vesicles or other synaptic markers. We fused the state-of-the-art reporter iGluSnFR to glutamate receptor auxiliary proteins in order to target it to postsynaptic sites. Chimeras of Stargazin and gamma-8 that we named SnFR-γ2 and SnFR-γ8, were enriched at synapses, retained function and reported spontaneous glutamate release in rat hippocampal cells, with apparently diffraction-limited spatial precision. In autaptic mouse neurons cultured on astrocytic microislands, evoked neurotransmitter release could be quantitatively detected at tens of synapses in a field of view whilst evoked currents were recorded simultaneously. These experiments revealed a specific postsynaptic deficit from Stargazin overexpression, resulting in synapses with normal neurotransmitter release but without postsynaptic responses. This defect was reverted by delaying overexpression. By working at different calcium concentrations, we determined that SnFR-γ2 is a linear reporter of the global quantal parameters and short-term synaptic plasticity, whereas iGluSnFR is not. On average, half of iGluSnFR regions of interest (ROIs) showing evoked fluorescence changes had intense rundown, whereas less than 5% of SnFR-γ2 ROIs did. We provide an open-source analysis suite for extracting quantal parameters including release probability from fluorescence time series of individual and grouped synaptic responses. Taken together, postsynaptic targeting improves several properties of iGluSnFR and further demonstrates the importance of subcellular targeting for optogenetic actuators and reporters.
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Affiliation(s)
- Yuchen Hao
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
| | - Estelle Toulmé
- Institute for Neurophysiology, Charité - Universitätsmedizin BerlinBerlinGermany
| | - Benjamin König
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
| | - Christian Rosenmund
- Institute for Neurophysiology, Charité - Universitätsmedizin BerlinBerlinGermany
- NeuroCure Cluster of ExcellenceBerlinGermany
| | - Andrew JR Plested
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
- NeuroCure Cluster of ExcellenceBerlinGermany
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27
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Moretto E, Miozzo F, Longatti A, Bonnet C, Coussen F, Jaudon F, Cingolani LA, Passafaro M. The tetraspanin TSPAN5 regulates AMPAR exocytosis by interacting with the AP4 complex. eLife 2023; 12:76425. [PMID: 36795458 PMCID: PMC9934860 DOI: 10.7554/elife.76425] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/25/2023] [Indexed: 02/17/2023] Open
Abstract
Intracellular trafficking of AMPA receptors is a tightly regulated process which involves several adaptor proteins, and is crucial for the activity of excitatory synapses both in basal conditions and during synaptic plasticity. We found that, in rat hippocampal neurons, an intracellular pool of the tetraspanin TSPAN5 promotes exocytosis of AMPA receptors without affecting their internalisation. TSPAN5 mediates this function by interacting with the adaptor protein complex AP4 and Stargazin and possibly using recycling endosomes as a delivery route. This work highlights TSPAN5 as a new adaptor regulating AMPA receptor trafficking.
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Affiliation(s)
- Edoardo Moretto
- Institute of Neuroscience, CNRVedano al LambroItaly,NeuroMI Milan Center for Neuroscience, University of Milano-BicoccaMilanItaly
| | | | | | - Caroline Bonnet
- University of Bordeaux, Interdisciplinary Institute for NeuroscienceBordeauxFrance
| | - Francoise Coussen
- University of Bordeaux, Interdisciplinary Institute for NeuroscienceBordeauxFrance
| | - Fanny Jaudon
- Department of Life Sciences, University of TriesteTriesteItaly,IRCCS Ospedale Policlinico San MartinoGenoaItaly
| | - Lorenzo A Cingolani
- Department of Life Sciences, University of TriesteTriesteItaly,Center for Synaptic Neuroscience and Technology (NSYN), Istituto Italiano di Tecnologia (IIT)GenoaItaly
| | - Maria Passafaro
- Institute of Neuroscience, CNRVedano al LambroItaly,NeuroMI Milan Center for Neuroscience, University of Milano-BicoccaMilanItaly
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28
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Lee YH, Suh BK, Lee U, Ryu SH, Shin SR, Chang S, Park SK, Chung KC. DYRK3 phosphorylates SNAPIN to regulate axonal retrograde transport and neurotransmitter release. Cell Death Dis 2022; 8:503. [PMID: 36585413 PMCID: PMC9803678 DOI: 10.1038/s41420-022-01290-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 12/31/2022]
Abstract
Among the five members of the dual-specificity tyrosine-phosphorylation-regulated kinase (DYRK) family, the cellular functions of DYRK3 have not been fully elucidated. Some studies have indicated limited physiological roles and substrates of DYRK3, including promotion of glioblastoma, requirement in influenza virus replication, and coupling of stress granule condensation with mammalian target of rapamycin complex 1 signaling. Here, we demonstrate that serum deprivation causes a decrease in intracellular DYRK3 levels via the proteolytic autophagy pathway, as well as the suppression of DYRK3 gene expression. To further demonstrate how DYRK3 affects cell viability, especially in neurons, we used a yeast two-hybrid assay and identified multiple DYRK3-binding proteins, including SNAPIN, a SNARE-associated protein implicated in synaptic transmission. We also found that DYRK3 directly phosphorylates SNAPIN at the threonine (Thr) 14 residue, increasing the interaction of SNAPIN with other proteins such as dynein and synaptotagmin-1. In central nervous system neurons, SNAPIN is associated with and mediate the retrograde axonal transport of diverse cellular products from the distal axon terminal to the soma and the synaptic release of neurotransmitters, respectively. Moreover, phosphorylation of SNAPIN at Thr-14 was found to positively modulate mitochondrial retrograde transport in mouse cortical neurons and the recycling pool size of synaptic vesicles, contributing to neuronal viability. In conclusion, the present study demonstrates that DYRK3 phosphorylates SNAPIN, positively regulating the dynein-mediated retrograde transport of mitochondria and SNARE complex-mediated exocytosis of synaptic vesicles within the neurons. This finding further suggests that DYRK3 affects cell viability and provides a novel neuroprotective mechanism.
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Affiliation(s)
- Ye Hyung Lee
- grid.15444.300000 0004 0470 5454Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Bo Kyoung Suh
- grid.49100.3c0000 0001 0742 4007Department of Life Sciences, Pohang University of Science and Technology, Pohang-si, Gyeongsangbuk-do Korea
| | - Unghwi Lee
- grid.31501.360000 0004 0470 5905Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Seung Hyun Ryu
- grid.31501.360000 0004 0470 5905Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Ryong Shin
- grid.49100.3c0000 0001 0742 4007Department of Life Sciences, Pohang University of Science and Technology, Pohang-si, Gyeongsangbuk-do Korea
| | - Sunghoe Chang
- grid.31501.360000 0004 0470 5905Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Sang Ki Park
- grid.49100.3c0000 0001 0742 4007Department of Life Sciences, Pohang University of Science and Technology, Pohang-si, Gyeongsangbuk-do Korea
| | - Kwang Chul Chung
- grid.15444.300000 0004 0470 5454Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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29
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Cocaine-regulated trafficking of dopamine transporters in cultured neurons revealed by a pH sensitive reporter. iScience 2022; 26:105782. [PMID: 36594015 PMCID: PMC9804146 DOI: 10.1016/j.isci.2022.105782] [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: 08/18/2022] [Revised: 11/07/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
Cocaine acts by inhibiting plasma membrane dopamine transporter (DAT) function and altering its surface expression. The precise manner and mechanism by which cocaine regulates DAT trafficking, especially at neuronal processes, are poorly understood. In this study, we engineered and validated the use of DAT-pHluorin for studying DAT localization and its dynamic trafficking at neuronal processes of cultured mouse midbrain neurons. We demonstrate that unlike neuronal soma and dendrites, which contain a majority of the DATs in weakly acidic intracellular compartments, axonal DATs at both shafts and boutons are primarily (75%) localized to the plasma membrane, whereas large varicosities contain abundant intracellular DAT within acidic intracellular structures. We also demonstrate that cocaine exposure leads to a Synaptojanin1-sensitive DAT internalization process followed by membrane reinsertion that lasts for days. Thus, our study reveals the previously unknown dynamics and molecular regulation for cocaine-regulated DAT trafficking in neuronal processes.
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Girven KS, Mangieri L, Bruchas MR. Emerging approaches for decoding neuropeptide transmission. Trends Neurosci 2022; 45:899-912. [PMID: 36257845 PMCID: PMC9671847 DOI: 10.1016/j.tins.2022.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/14/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022]
Abstract
Neuropeptides produce robust effects on behavior across species, and recent research has benefited from advances in high-resolution techniques to investigate peptidergic transmission and expression throughout the brain in model systems. Neuropeptides exhibit distinct characteristics which includes their post-translational processing, release from dense core vesicles, and ability to activate G-protein-coupled receptors (GPCRs). These complex properties have driven the need for development of specialized tools that can sense neuropeptide expression, cell activity, and release. Current research has focused on isolating when and how neuropeptide transmission occurs, as well as the conditions in which neuropeptides directly mediate physiological and adaptive behavioral states. Here we describe the current technological landscape in which the field is operating to decode key questions regarding these dynamic neuromodulators.
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Affiliation(s)
- Kasey S Girven
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA; University of Washington Center for the Neurobiology of Addiction, Pain, and Emotion, Seattle, WA, USA; Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Leandra Mangieri
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA; University of Washington Center for the Neurobiology of Addiction, Pain, and Emotion, Seattle, WA, USA
| | - Michael R Bruchas
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA; University of Washington Center for the Neurobiology of Addiction, Pain, and Emotion, Seattle, WA, USA; Department of Pharmacology, University of Washington, Seattle, WA, USA.
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31
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Altered signaling at the PTH receptor via modified agonist contacts with the extracellular domain provides a path to prolonged agonism in vivo. Proc Natl Acad Sci U S A 2022; 119:e2212736119. [PMID: 36409914 PMCID: PMC9860328 DOI: 10.1073/pnas.2212736119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The parathyroid hormone type 1 receptor (PTHR1), a Class B GPCR, is activated by long polypeptides, including drugs for osteoporosis and hypoparathyroidism. The PTHR1 engages peptide agonists via a two-step mechanism. Initial contact involves the extracellular domain (ECD), which has been thought to contribute primarily to receptor-peptide binding, and then the N terminus of the peptide engages the receptor transmembrane domain (TMD), which is thought to control the message conveyed to intracellular partners. This mechanism has been suggested to apply to other Class B GPCRs as well. Here, we show that modification of a PTHR1 agonist at ECD-contact sites can alter the signaling profile, an outcome that is not accommodated by the current two-step binding model. Our data support a modified two-step binding model in which agonist orientation on the ECD surface can influence the geometry of agonist-TMD engagement. This expanded binding model offers a mechanism by which altering ECD-contact residues can affect signaling profile. Our discoveries provide a rationale for exploring agonist modifications distal from the TMD-contact region in future efforts to optimize therapeutic performance of peptide hormone analogs.
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Frank M, Nabb AT, Gilbert SP, Bentley M. Propofol attenuates kinesin-mediated axonal vesicle transport and fusion. Mol Biol Cell 2022; 33:ar119. [PMID: 36103253 PMCID: PMC9634964 DOI: 10.1091/mbc.e22-07-0276] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Propofol is a widely used general anesthetic, yet the understanding of its cellular effects is fragmentary. General anesthetics are not as innocuous as once believed and have a wide range of molecular targets that include kinesin motors. Propofol, ketamine, and etomidate reduce the distances that Kinesin-1 KIF5 and Kinesin-2 KIF3 travel along microtubules in vitro. These transport kinesins are highly expressed in the CNS, and their dysfunction leads to a range of human pathologies including neurodevelopmental and neurodegenerative diseases. While in vitro data suggest that general anesthetics may disrupt kinesin transport in neurons, this hypothesis remains untested. Here we find that propofol treatment of hippocampal neurons decreased vesicle transport mediated by Kinesin-1 KIF5 and Kinesin-3 KIF1A ∼25-60%. Propofol treatment delayed delivery of the KIF5 cargo NgCAM to the distal axon. Because KIF1A participates in axonal transport of presynaptic vesicles, we tested whether prolonged propofol treatment affects synaptic vesicle fusion mediated by VAMP2. The data show that propofol-induced transport delay causes a significant decrease in vesicle fusion in distal axons. These results are the first to link a propofol-induced delay in neuronal trafficking to a decrease in axonal vesicle fusion, which may alter physiological function during and after anesthesia.
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Affiliation(s)
- Madeline Frank
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Alec T. Nabb
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Susan P. Gilbert
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Marvin Bentley
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180,*Address correspondence to: Marvin Bentley ()
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Differential trafficking of ligands trogocytosed via CD28 versus CTLA4 promotes collective cellular control of co-stimulation. Nat Commun 2022; 13:6459. [PMID: 36309492 PMCID: PMC9617924 DOI: 10.1038/s41467-022-34156-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 10/14/2022] [Indexed: 12/25/2022] Open
Abstract
Intercellular communication is crucial for collective regulation of cellular behaviors. While clustering T cells have been shown to mutually control the production of key communication signals, it is unclear whether they also jointly regulate their availability and degradation. Here we use newly developed reporter systems, bioinformatic analyses, protein structure modeling and genetic perturbations to assess this. We find that T cells utilize trogocytosis by competing antagonistic receptors to differentially control the abundance of immunoregulatory ligands. Specifically, ligands trogocytosed via CD28 are shuttled to the T cell surface, enabling them to co-stimulate neighboring T cells. In contrast, CTLA4-mediated trogocytosis targets ligands for degradation. Mechanistically, this fate separation is controlled by different acid-sensitivities of receptor-ligand interactions and by the receptor intracellular domains. The ability of CD28 and CTLA4 to confer different fates to trogocytosed ligands reveals an additional layer of collective regulation of cellular behaviors and promotes the robustness of population dynamics.
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34
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Wong HTC, Drerup CM. Using fluorescent indicators for in vivo quantification of spontaneous or evoked motor neuron presynaptic activity in transgenic zebrafish. STAR Protoc 2022; 3:101766. [PMID: 36240058 PMCID: PMC9568885 DOI: 10.1016/j.xpro.2022.101766] [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: 07/01/2022] [Revised: 08/22/2022] [Accepted: 09/20/2022] [Indexed: 11/07/2022] Open
Abstract
In this protocol, we describe steps that utilize the optical clarity of the zebrafish larvae and the stereotyped motor neuron axon structure in the trunk to measure spontaneous or evoked motor neuron axon activity. This activity is detected with transgenic fluorescent indicators introduced into the larvae by zygotic injection. Fluorescent indicator intensity changes in the small neuromuscular junctions are quantified to measure the presynaptic calcium activity and consequent synaptic vesicle release. For complete details on the use and execution of this protocol, please refer to Mandal et al. (2020).
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Affiliation(s)
- Hiu-tung Candy Wong
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA,Corresponding author
| | - Catherine M. Drerup
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA,Corresponding author
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35
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Francis CR, Kushner EJ. Capturing membrane trafficking events during 3D angiogenic development in vitro. Microcirculation 2022; 29:e12726. [PMID: 34415654 PMCID: PMC8858330 DOI: 10.1111/micc.12726] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 08/10/2021] [Accepted: 08/16/2021] [Indexed: 12/30/2022]
Abstract
OBJECTIVES Vesicular trafficking dictates protein localization, functional activity, and half-life, providing a critically important regulatory step in tissue development; however, there is little information detailing endothelial-specific trafficking signatures. This is due, in part, to limitations in visualizing trafficking events in endothelial tissues. Our aim in this investigation was to explore the use of a 3-dimensional (3D) in vitro sprouting model to image endothelial membrane trafficking events. METHODS Endothelial cells were challenged to grow sprouts in a fibrin bead assay. Thereafter, spouts were transfected with fluorescent proteins and stained for various cell markers. Sprouts were then imaged for trafficking events using live and fixed-cell microscopy. RESULTS Our results demonstrate that fibrin bead sprouts have a strong apicobasal polarity marked by apical localization of proteins moesin and podocalyxin. Comparison of trafficking mediators Rab27a and Rab35 between 3D sprouts and 2D culture showed that vesicular carriers can be imaged at high resolution, exhibiting proper membrane polarity solely in 3D sprouts. Lastly, we imaged exocytic events of von Willebrand Factor and demonstrated a distinct imaging advantage for monitoring secretion events in 3D sprouts as compared with 2D culture. CONCLUSIONS Our results establish that the fibrin bead sprouting assay is well-suited for imaging of trafficking events during angiogenic growth.
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Affiliation(s)
| | - Erich J. Kushner
- Department of Biological SciencesUniversity of DenverDenverColoradoUSA
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36
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Burgstaller S, Wagner TR, Bischof H, Bueckle S, Padamsey A, Frecot D, Kaiser PD, Skrabak D, Malli R, Lukowski R, Rothbauer U. Monitoring extracellular ion and metabolite dynamics with recombinant nanobody-fused biosensors. iScience 2022; 25:104907. [PMID: 36046190 PMCID: PMC9421384 DOI: 10.1016/j.isci.2022.104907] [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: 04/13/2022] [Revised: 06/29/2022] [Accepted: 08/05/2022] [Indexed: 11/29/2022] Open
Abstract
Ion and analyte changes in the tumor microenvironment (TME) alter the metabolic activity of cancer cells, promote tumor cell growth, and impair anti-tumor immunity. Consequently, accurate determination and visualization of extracellular changes of analytes in real time is desired. In this study, we genetically combined FRET-based biosensors with nanobodies (Nbs) to specifically visualize and monitor extracellular changes in K+, pH, and glucose on cell surfaces. We demonstrated that these Nb-fused biosensors quantitatively visualized K+ alterations on cancer and non-cancer cell lines and primary neurons. By implementing a HER2-specific Nb, we generated functional K+ and pH sensors, which specifically stained HER2-positive breast cancer cells. Based on the successful development of several Nb-fused biosensor combinations, we anticipate that this approach can be readily extended to other biosensors and will open new opportunities for the study of extracellular analytes in advanced experimental settings. Generation of recombinant nanobody-fused FRET biosensors Nb-fused biosensors specifically bind targets on the outer surface of various cells Cellular bound Nb-biosensors visualize extracellular analyte changes in real time
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Affiliation(s)
- Sandra Burgstaller
- Pharmaceutical Biotechnology, Eberhard Karls University Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany.,Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany
| | - Teresa R Wagner
- Pharmaceutical Biotechnology, Eberhard Karls University Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany.,NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany
| | - Helmut Bischof
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany
| | - Sarah Bueckle
- Pharmaceutical Biotechnology, Eberhard Karls University Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany
| | - Aman Padamsey
- Pharmaceutical Biotechnology, Eberhard Karls University Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany
| | - Desiree Frecot
- Pharmaceutical Biotechnology, Eberhard Karls University Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany.,NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany
| | - Philipp D Kaiser
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany
| | - David Skrabak
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany
| | - Roland Malli
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria.,BioTechMed-Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany
| | - Ulrich Rothbauer
- Pharmaceutical Biotechnology, Eberhard Karls University Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany.,NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany
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37
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Oh Y, Lee W, Kim SH, Lee S, Kim BC, Lee KH, Kim SH, Song WK. SPIN90 Deficiency Ameliorates Amyloid β Accumulation by Regulating APP Trafficking in AD Model Mice. Int J Mol Sci 2022; 23:ijms231810563. [PMID: 36142484 PMCID: PMC9504172 DOI: 10.3390/ijms231810563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
Alzheimer’s disease (AD), a common form of dementia, is caused in part by the aggregation and accumulation in the brain of amyloid β (Aβ), a product of the proteolytic cleavage of amyloid precursor protein (APP) in endosomes. Trafficking of APP, such as surface-intracellular recycling, is an early critical step required for Aβ generation. Less is known, however, about the molecular mechanism regulating APP trafficking. This study investigated the mechanism by which SPIN90, along with Rab11, modulates APP trafficking, Aβ motility and accumulation, and synaptic functionality. Brain Aβ deposition was lower in the progeny of 5xFAD-SPIN90KO mice than in 5xFAD-SPIN90WT mice. Analysis of APP distribution and trafficking showed that the surface fraction of APP was locally distinct in axons and dendrites, with these distributions differing significantly in 5xFAD-SPIN90WT and 5xFAD-SPIN90KO mice, and that neural activity-driven APP trafficking to the surface and intracellular recycling were more actively mobilized in 5xFAD-SPIN90KO neurons. In addition, SPIN90 was found to be cotrafficked with APP via axons, with ablation of SPIN90 reducing the intracellular accumulation of APP in axons. Finally, synaptic transmission was restored over time in 5xFAD-SPIN90KO but not in 5xFAD-SPIN90WT neurons, suggesting SPIN90 is implicated in Aβ production through the regulation of APP trafficking.
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Affiliation(s)
- Youngsoo Oh
- Cell Logistics Research Center, School of Life Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Wongyoung Lee
- Department of Neuroscience, Graduate School, Kyung Hee University, Seoul 02447, Korea
| | - So Hee Kim
- Cell Logistics Research Center, School of Life Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Sooji Lee
- Department of Medicine, School of Medicine, Kyung Hee University, Seoul 02447, Korea
| | - Byeong C. Kim
- Department of Neurology, Chonnam National University Medical School, Gwangju 61469, Korea
| | - Kun Ho Lee
- Gwangju Alzheimer’s Disease and Related Dementia Cohort Research Center, Chosun University, Gwangju 61452, Korea
| | - Sung Hyun Kim
- Department of Neuroscience, Graduate School, Kyung Hee University, Seoul 02447, Korea
- Department of Physiology, School of Medicine, Kyung Hee University, Seoul 02447, Korea
- Correspondence: (S.H.K.); (W.K.S.)
| | - Woo Keun Song
- Cell Logistics Research Center, School of Life Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
- Correspondence: (S.H.K.); (W.K.S.)
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38
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Bayonés L, Guerra-Fernández MJ, Hinostroza F, Báez-Matus X, Vásquez-Navarrete J, Gallo LI, Parra S, Martínez AD, González-Jamett A, Marengo FD, Cárdenas AM. Gain-of-Function Dynamin-2 Mutations Linked to Centronuclear Myopathy Impair Ca2+-Induced Exocytosis in Human Myoblasts. Int J Mol Sci 2022; 23:ijms231810363. [PMID: 36142275 PMCID: PMC9499313 DOI: 10.3390/ijms231810363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/26/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
Gain-of-function mutations of dynamin-2, a mechano-GTPase that remodels membrane and actin filaments, cause centronuclear myopathy (CNM), a congenital disease that mainly affects skeletal muscle tissue. Among these mutations, the variants p.A618T and p.S619L lead to a gain of function and cause a severe neonatal phenotype. By using total internal reflection fluorescence microscopy (TIRFM) in immortalized human myoblasts expressing the pH-sensitive fluorescent protein (pHluorin) fused to the insulin-responsive aminopeptidase IRAP as a reporter of the GLUT4 vesicle trafficking, we measured single pHluorin signals to investigate how p.A618T and p.S619L mutations influence exocytosis. We show here that both dynamin-2 mutations significantly reduced the number and durations of pHluorin signals induced by 10 μM ionomycin, indicating that in addition to impairing exocytosis, they also affect the fusion pore dynamics. These mutations also disrupt the formation of actin filaments, a process that reportedly favors exocytosis. This altered exocytosis might importantly disturb the plasmalemma expression of functional proteins such as the glucose transporter GLUT4 in skeletal muscle cells, impacting the physiology of the skeletal muscle tissue and contributing to the CNM disease.
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Affiliation(s)
- Lucas Bayonés
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - María José Guerra-Fernández
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Fernando Hinostroza
- Centro de Investigación de Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca 3460000, Chile
- Centro de Investigación en Neuropsicología y Neurociencias Cognitivas (CINPSI Neurocog), Facultad de Ciencias de la Salud, Universidad Católica del Maule, Talca 3460000, Chile
| | - Ximena Báez-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Jacqueline Vásquez-Navarrete
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Luciana I. Gallo
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Sergio Parra
- Instituto de Fisiología Celular—Neurociencias, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Arlek González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Fernando D. Marengo
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
- Correspondence: (F.D.M.); (A.M.C.)
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
- Correspondence: (F.D.M.); (A.M.C.)
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Monitoring cell membrane recycling dynamics of proteins using whole-cell fluorescence recovery after photobleaching of pH-sensitive genetic tags. Nat Protoc 2022; 17:3056-3079. [PMID: 36064755 DOI: 10.1038/s41596-022-00732-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 06/07/2022] [Indexed: 11/08/2022]
Abstract
Population behavior of signaling molecules on the cell surface is key to their adaptive function. Live imaging of proteins tagged with fluorescent molecules has been an essential tool in understanding this behavior. Typically, genetic or chemical tags are used to target molecules present throughout the cell, whereas antibody-based tags label the externally exposed molecular domains only. Both approaches could potentially overlook the intricate process of in-out membrane recycling in which target molecules appear or disappear on the cell surface. This limitation is overcome by using a pH-sensitive fluorescent tag, such as Super-Ecliptic pHluorin (SEP), because its emission depends on whether it resides inside or outside the cell. Here we focus on the main glial glutamate transporter GLT1 and describe a genetic design that equips GLT1 molecules with SEP without interfering with the transporter's main function. Expressing GLT1-SEP in astroglia in cultures or in hippocampal slices enables monitoring of the real-time dynamics of the cell-surface and cytosolic fractions of the transporter in living cells. Whole-cell fluorescence recovery after photobleaching and quantitative image-kinetic analysis of the resulting time-lapse images enables assessment of the rate of GLT1-SEP recycling on the cell surface, a fundamental trafficking parameter unattainable previously. The present protocol takes 15-20 d to set up cell preparations, and 2-3 d to carry out live cell experiments and data analyses. The protocol can be adapted to study different membrane molecules of interest, particularly those proteins whose lifetime on the cell surface is critical to their adaptive function.
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Activity-dependent endoplasmic reticulum Ca 2+ uptake depends on Kv2.1-mediated endoplasmic reticulum/plasma membrane junctions to promote synaptic transmission. Proc Natl Acad Sci U S A 2022; 119:e2117135119. [PMID: 35862456 PMCID: PMC9335237 DOI: 10.1073/pnas.2117135119] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The endoplasmic reticulum (ER) extends throughout the neuron as a continuous organelle, and its dysfunction is associated with several neurological disorders. During electrical activity, the ER takes up Ca2+ from the cytosol, which has been shown to support synaptic transmission. This close choreography of ER Ca2+ uptake with electrical activity suggests functional coupling of the ER to sources of voltage-gated Ca2+ entry through an unknown mechanism. We report that a nonconducting role for Kv2.1 through its ER binding domain is necessary for ER Ca2+ uptake during neuronal activity. Loss of Kv2.1 profoundly disables neurotransmitter release without altering presynaptic voltage. This suggests that Kv2.1-mediated signaling hubs play an important neurobiological role in Ca2+ handling and synaptic transmission independent of ion conduction. The endoplasmic reticulum (ER) forms a continuous and dynamic network throughout a neuron, extending from dendrites to axon terminals, and axonal ER dysfunction is implicated in several neurological disorders. In addition, tight junctions between the ER and plasma membrane (PM) are formed by several molecules including Kv2 channels, but the cellular functions of many ER-PM junctions remain unknown. Recently, dynamic Ca2+ uptake into the ER during electrical activity was shown to play an essential role in synaptic transmission. Our experiments demonstrate that Kv2.1 channels are necessary for enabling ER Ca2+ uptake during electrical activity, as knockdown (KD) of Kv2.1 rendered both the somatic and axonal ER unable to accumulate Ca2+ during electrical stimulation. Moreover, our experiments demonstrate that the loss of Kv2.1 in the axon impairs synaptic vesicle fusion during stimulation via a mechanism unrelated to voltage. Thus, our data demonstrate that a nonconducting role of Kv2.1 exists through its binding to the ER protein VAMP-associated protein (VAP), which couples ER Ca2+ uptake with electrical activity. Our results further suggest that Kv2.1 has a critical function in neuronal cell biology for Ca2+ handling independent of voltage and reveals a critical pathway for maintaining ER lumen Ca2+ levels and efficient neurotransmitter release. Taken together, these findings reveal an essential nonclassical role for both Kv2.1 and the ER-PM junctions in synaptic transmission.
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Acidification of endothelial Weibel-Palade bodies is mediated by the vacuolar-type H+-ATPase. PLoS One 2022; 17:e0270299. [PMID: 35767558 PMCID: PMC9242466 DOI: 10.1371/journal.pone.0270299] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/07/2022] [Indexed: 12/02/2022] Open
Abstract
Weibel-Palade bodies (WPB) are unique secretory granules of endothelial cells that store the procoagulant von-Willebrand factor (VWF) in a highly compacted form. Upon exocytosis the densely packed VWF unfurls into long strands that expose binding sites for circulating platelets and thereby initiate the formation of a platelet plug at sites of blood vessel injury. Dense packing of VWF requires the establishment of an acidic pH in the lumen of maturing WPB but the mechanism responsible for this acidification has not yet been fully established. We show here that subunits of the vacuolar-type H+-ATPase are present on mature WPB and that interference with the proton pump activity of the ATPase employing inhibitors of different chemical nature blocks a reduction in the relative internal pH of WPB. Furthermore, depletion of the V-ATPase subunit V0d1 from primary endothelial cells prevents WPB pH reduction and the establishment of an elongated morphology of WPB that is dictated by the densely packed VWF tubules. Thus, the vacuolar-type H+-ATPase present on WPB is required for proper acidification and maturation of the organelle.
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Jung S, Zimin PI, Woods CB, Kayser EB, Haddad D, Reczek CR, Nakamura K, Ramirez JM, Sedensky MM, Morgan PG. Isoflurane inhibition of endocytosis is an anesthetic mechanism of action. Curr Biol 2022; 32:3016-3032.e3. [PMID: 35688155 PMCID: PMC9329204 DOI: 10.1016/j.cub.2022.05.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 03/30/2022] [Accepted: 05/13/2022] [Indexed: 10/18/2022]
Abstract
The mechanisms of volatile anesthetic action remain among the most perplexing mysteries of medicine. Across phylogeny, volatile anesthetics selectively inhibit mitochondrial complex I, and they also depress presynaptic excitatory signaling. To explore how these effects are linked, we studied isoflurane effects on presynaptic vesicle cycling and ATP levels in hippocampal cultured neurons from wild-type and complex I mutant (Ndufs4(KO)) mice. To bypass complex I, we measured isoflurane effects on anesthetic sensitivity in mice expressing NADH dehydrogenase (NDi1). Endocytosis in physiologic concentrations of glucose was delayed by effective behavioral concentrations of isoflurane in both wild-type (τ [unexposed] 44.8 ± 24.2 s; τ [exposed] 116.1 ± 28.1 s; p < 0.01) and Ndufs4(KO) cultures (τ [unexposed] 67.6 ± 16.0 s; τ [exposed] 128.4 ± 42.9 s; p = 0.028). Increasing glucose, to enhance glycolysis and increase ATP production, led to maintenance of both ATP levels and endocytosis (τ [unexposed] 28.0 ± 14.4; τ [exposed] 38.2 ± 5.7; reducing glucose worsened ATP levels and depressed endocytosis (τ [unexposed] 85.4 ± 69.3; τ [exposed] > 1,000; p < 0.001). The block in recycling occurred at the level of reuptake of synaptic vesicles into the presynaptic cell. Expression of NDi1 in wild-type mice caused behavioral resistance to isoflurane for tail clamp response (EC50 Ndi1(-) 1.27% ± 0.14%; Ndi1(+) 1.55% ± 0.13%) and halothane (EC50 Ndi1(-) 1.20% ± 0.11%; Ndi1(+) 1.46% ± 0.10%); expression of NDi1 in neurons improved hippocampal function, alleviated inhibition of presynaptic recycling, and increased ATP levels during isoflurane exposure. The clear alignment of cell culture data to in vivo phenotypes of both isoflurane-sensitive and -resistant mice indicates that inhibition of mitochondrial complex I is a primary mechanism of action of volatile anesthetics.
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Affiliation(s)
- Sangwook Jung
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Pavel I Zimin
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA
| | - Christian B Woods
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Ernst-Bernhard Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Dominik Haddad
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Colleen R Reczek
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ken Nakamura
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Neurological Surgery, University of Washington, Seattle, WA 98105, USA
| | - Margaret M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA
| | - Philip G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA.
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Lopez-Manzaneda M, Fuentes-Moliz A, Tabares L. Presynaptic Mitochondria Communicate With Release Sites for Spatio-Temporal Regulation of Exocytosis at the Motor Nerve Terminal. Front Synaptic Neurosci 2022; 14:858340. [PMID: 35645766 PMCID: PMC9133601 DOI: 10.3389/fnsyn.2022.858340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
Presynaptic Ca2+ regulation is critical for accurate neurotransmitter release, vesicle reloading of release sites, and plastic changes in response to electrical activity. One of the main players in the regulation of cytosolic Ca2+ in nerve terminals is mitochondria, which control the size and spread of the Ca2+ wave during sustained electrical activity. However, the role of mitochondria in Ca2+ signaling during high-frequency short bursts of action potentials (APs) is not well known. Here, we studied spatial and temporal relationships between mitochondrial Ca2+ (mCa2+) and exocytosis by live imaging and electrophysiology in adult motor nerve terminals of transgenic mice expressing synaptophysin-pHluorin (SypHy). Our results show that hot spots of exocytosis and mitochondria are organized in subsynaptic functional regions and that mitochondria start to uptake Ca2+ after a few APs. We also show that mitochondria contribute to the regulation of the mode of fusion (synchronous and asynchronous) and the kinetics of release and replenishment of the readily releasable pool (RRP) of vesicles. We propose that mitochondria modulate the timing and reliability of neurotransmission in motor nerve terminals during brief AP trains.
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Wu SY, Shen Y, Shkolnikov I, Campbell RE. Fluorescent Indicators For Biological Imaging of Monatomic Ions. Front Cell Dev Biol 2022; 10:885440. [PMID: 35573682 PMCID: PMC9093666 DOI: 10.3389/fcell.2022.885440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Monatomic ions play critical biological roles including maintaining the cellular osmotic pressure, transmitting signals, and catalyzing redox reactions as cofactors in enzymes. The ability to visualize monatomic ion concentration, and dynamic changes in the concentration, is essential to understanding their many biological functions. A growing number of genetically encodable and synthetic indicators enable the visualization and detection of monatomic ions in biological systems. With this review, we aim to provide a survey of the current landscape of reported indicators. We hope this review will be a useful guide to researchers who are interested in using indicators for biological applications and to tool developers seeking opportunities to create new and improved indicators.
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Affiliation(s)
- Sheng-Yi Wu
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Yi Shen
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Irene Shkolnikov
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Department of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Robert E. Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Department of Chemistry, The University of Tokyo, Tokyo, Japan
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Egashira Y, Kumade A, Ojida A, Ono F. Spontaneously Recycling Synaptic Vesicles Constitute Readily Releasable Vesicles in Intact Neuromuscular Synapses. J Neurosci 2022; 42:3523-3536. [PMID: 35332083 PMCID: PMC9053852 DOI: 10.1523/jneurosci.2005-21.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/08/2022] [Accepted: 03/10/2022] [Indexed: 12/14/2022] Open
Abstract
Emerging evidence shows that spontaneous synaptic transmission plays crucial roles on neuronal functions through presynaptic molecular mechanisms distinct from that of action potential (AP)-evoked transmission. However, whether the synaptic vesicle (SV) population undergoing the two forms of transmission is segregated remains controversial due in part to the conflicting results observed in cultured neurons. Here we address this issue in intact neuromuscular synapses using transgenic zebrafish larvae expressing two different indicators targeted in the SVs: a pH-sensitive fluorescent protein, pHluorin, and a tag protein, HaloTag. By establishing a quantitative measure of recycled SV fractions, we found that ∼85% of SVs were mobilized by high-frequency AP firings. In contrast, spontaneously recycling SVs were mobilized only from <8% of SVs with a time constant of 45 min at 25°C, although prolonged AP inhibition mobilized an additional population with a delayed onset. The mobilization of the early-onset population was less temperature-sensitive and resistant to tetanus toxin, whereas that of the late-onset population was more sensitive to temperature and was inhibited by tetanus toxin, indicating that prolonged AP inhibition activated a distinct molecular machinery for spontaneous SV fusion. Therefore, the early-onset population limited to <8% was likely the only source of spontaneous release that occurred physiologically. We further showed that this limited population was independent from those reluctant to fuse during AP firing and was used in both the hypertonic stimulation and the immediate phase of AP-evoked releases, thereby matching the characteristics of the readily releasable pool.SIGNIFICANCE STATEMENT Synaptic vesicles (SVs) are divided into functionally distinct pools depending on how they respond to action potential (AP) firing. The origin of SVs used for spontaneous fusion remains enigmatic despite intensive studies in cultured preparations. We addressed this question in intact neuromuscular synapses and provided two findings. First, prolonged AP inhibition activated a distinct population of fusion, which needs to be distinguished from genuine spontaneous fusion arising from a highly limited fraction. Second, the limited fraction observed early in the AP inhibition period exhibited the characteristics of readily releasable pool in the subsequent round of stimulation. Our study revealed that the origin of spontaneous SV fusion is restricted to the readily releasable pool among the SV pools involved in AP-evoked fusion.
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Affiliation(s)
- Yoshihiro Egashira
- Department of Physiology, Osaka Medical and Pharmaceutical University, Takatsuki, 569-8686, Japan
| | - Ayane Kumade
- Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, 812-8582, Japan
| | - Akio Ojida
- Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, 812-8582, Japan
| | - Fumihito Ono
- Department of Physiology, Osaka Medical and Pharmaceutical University, Takatsuki, 569-8686, Japan
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46
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Serrano ME, Kim E, Petrinovic MM, Turkheimer F, Cash D. Imaging Synaptic Density: The Next Holy Grail of Neuroscience? Front Neurosci 2022; 16:796129. [PMID: 35401097 PMCID: PMC8990757 DOI: 10.3389/fnins.2022.796129] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/15/2022] [Indexed: 12/19/2022] Open
Abstract
The brain is the central and most complex organ in the nervous system, comprising billions of neurons that constantly communicate through trillions of connections called synapses. Despite being formed mainly during prenatal and early postnatal development, synapses are continually refined and eliminated throughout life via complicated and hitherto incompletely understood mechanisms. Failure to correctly regulate the numbers and distribution of synapses has been associated with many neurological and psychiatric disorders, including autism, epilepsy, Alzheimer’s disease, and schizophrenia. Therefore, measurements of brain synaptic density, as well as early detection of synaptic dysfunction, are essential for understanding normal and abnormal brain development. To date, multiple synaptic density markers have been proposed and investigated in experimental models of brain disorders. The majority of the gold standard methodologies (e.g., electron microscopy or immunohistochemistry) visualize synapses or measure changes in pre- and postsynaptic proteins ex vivo. However, the invasive nature of these classic methodologies precludes their use in living organisms. The recent development of positron emission tomography (PET) tracers [such as (18F)UCB-H or (11C)UCB-J] that bind to a putative synaptic density marker, the synaptic vesicle 2A (SV2A) protein, is heralding a likely paradigm shift in detecting synaptic alterations in patients. Despite their limited specificity, novel, non-invasive magnetic resonance (MR)-based methods also show promise in inferring synaptic information by linking to glutamate neurotransmission. Although promising, all these methods entail various advantages and limitations that must be addressed before becoming part of routine clinical practice. In this review, we summarize and discuss current ex vivo and in vivo methods of quantifying synaptic density, including an evaluation of their reliability and experimental utility. We conclude with a critical assessment of challenges that need to be overcome before successfully employing synaptic density biomarkers as diagnostic and/or prognostic tools in the study of neurological and neuropsychiatric disorders.
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Affiliation(s)
- Maria Elisa Serrano
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Eugene Kim
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Marija M Petrinovic
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom
| | - Federico Turkheimer
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
| | - Diana Cash
- Department of Neuroimaging, The BRAIN Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, United Kingdom
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47
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The Plant Defense Signal Salicylic Acid Activates the RpfB-Dependent Quorum Sensing Signal Turnover via Altering the Culture and Cytoplasmic pH in the Phytopathogen Xanthomonas campestris. mBio 2022; 13:e0364421. [PMID: 35254135 PMCID: PMC9040794 DOI: 10.1128/mbio.03644-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Plant colonization by phytopathogens is a very complex process in which numerous factors are involved. Upon infection by phytopathogens, plants produce salicylic acid (SA) that triggers gene expression within the plant to counter the invading pathogens. The present study demonstrated that SA signal also directly acts on the quorum-sensing (QS) system of the invading pathogen Xanthomonas campestris pv. campestris to affect its virulence by inducing turnover of the diffusible signaling factor (DSF) family QS signal. First, Xanthomonas campestris pv. campestris infection induces SA biosynthesis in the cabbage host plant. SA cannot be degraded by Xanthomonas campestris pv. campestris during culturing. Exogenous addition of SA or endogenous production of SA induces DSF signal turnover during late growth phase of Xanthomonas campestris pv. campestris in XYS medium that mimics plant vascular environments. Further, the DSF turnover gene rpfB is required for SA induction of DSF turnover. However, SA does not affect the expression of rpfB and DSF biosynthesis gene rpfF at the transcriptional level. SA induction of DSF turnover only occurs under acidic conditions in XYS medium. Furthermore, addition of SA to XYS medium significantly increased both culture and cytoplasmic pH. Increased cytoplasmic pH induced DSF turnover in a rpfB-dependent manner. In vitro RpfB-dependent DSF turnover activity increased when pH increased from 6 to 8. SA exposure did not affect the RpfB-dependent DSF turnover in vitro. Finally, SA-treated Xanthomonas campestris pv. campestris strain exhibited enhanced virulence when inoculated on cabbage. These results provide new insight into the roles of SA in host plants and the molecular interactions between Xanthomonas campestris pv. campestris and cruciferous plants.
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48
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Campisi D, Desrues L, Dembélé KP, Mutel A, Parment R, Gandolfo P, Castel H, Morin F. The core autophagy protein ATG9A controls dynamics of cell protrusions and directed migration. J Cell Biol 2022; 221:e202106014. [PMID: 35180289 PMCID: PMC8932524 DOI: 10.1083/jcb.202106014] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 11/09/2021] [Accepted: 12/08/2021] [Indexed: 01/18/2023] Open
Abstract
Chemotactic migration is a fundamental cellular behavior relying on the coordinated flux of lipids and cargo proteins toward the leading edge. We found here that the core autophagy protein ATG9A plays a critical role in the chemotactic migration of several human cell lines, including highly invasive glioma cells. Depletion of ATG9A protein altered the formation of large and persistent filamentous actin (F-actin)-rich lamellipodia that normally drive directional migration. Using live-cell TIRF microscopy, we demonstrated that ATG9A-positive vesicles are targeted toward the migration front of polarized cells, where their exocytosis correlates with protrusive activity. Finally, we found that ATG9A was critical for efficient delivery of β1 integrin to the leading edge and normal adhesion dynamics. Collectively, our data uncover a new function for ATG9A protein and indicate that ATG9A-positive vesicles are mobilized during chemotactic stimulation to facilitate expansion of the lamellipodium and its anchorage to the extracellular matrix.
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Affiliation(s)
- Daniele Campisi
- Normandie University, UNIROUEN, Institut national de la santé et de la recherche médicale U1239, DC2N, Rouen, France
- Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Laurence Desrues
- Normandie University, UNIROUEN, Institut national de la santé et de la recherche médicale U1239, DC2N, Rouen, France
- Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Kléouforo-Paul Dembélé
- Normandie University, UNIROUEN, Institut national de la santé et de la recherche médicale U1239, DC2N, Rouen, France
- Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Alexandre Mutel
- Normandie University, UNIROUEN, Institut national de la santé et de la recherche médicale U1239, DC2N, Rouen, France
- Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Renaud Parment
- Normandie University, UNIROUEN, Institut national de la santé et de la recherche médicale U1239, DC2N, Rouen, France
- Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Pierrick Gandolfo
- Normandie University, UNIROUEN, Institut national de la santé et de la recherche médicale U1239, DC2N, Rouen, France
- Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Hélène Castel
- Normandie University, UNIROUEN, Institut national de la santé et de la recherche médicale U1239, DC2N, Rouen, France
- Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Fabrice Morin
- Normandie University, UNIROUEN, Institut national de la santé et de la recherche médicale U1239, DC2N, Rouen, France
- Institute for Research and Innovation in Biomedicine, Rouen, France
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Guhathakurta D, Akdaş EY, Fejtová A, Weiss EM. Development and Application of Automatized Routines for Optical Analysis of Synaptic Activity Evoked by Chemical and Electrical Stimulation. FRONTIERS IN BIOINFORMATICS 2022; 2:814081. [PMID: 36304276 PMCID: PMC9580924 DOI: 10.3389/fbinf.2022.814081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/24/2022] [Indexed: 11/24/2022] Open
Abstract
The recent development of cellular imaging techniques and the application of genetically encoded sensors of neuronal activity led to significant methodological progress in neurobiological studies. These methods often result in complex and large data sets consisting of image stacks or sets of multichannel fluorescent images. The detection of synapses, visualized by fluorescence labeling, is one major challenge in the analysis of these datasets, due to variations in synapse shape, size, and fluorescence intensity across the images. For their detection, most labs use manual or semi-manual techniques that are time-consuming and error-prone. We developed SynEdgeWs, a MATLAB-based segmentation algorithm that combines the application of an edge filter, morphological operators, and marker-controlled watershed segmentation. SynEdgeWs does not need training data and works with low user intervention. It was superior to methods based on cutoff thresholds and local maximum guided approaches in a realistic set of data. We implemented SynEdgeWs in two automatized routines that allow accurate, direct, and unbiased identification of fluorescently labeled synaptic puncta and their consecutive analysis. SynEval routine enables the analysis of three-channel images, and ImgSegRout routine processes image stacks. We tested the feasibility of ImgSegRout on a realistic live-cell imaging data set from experiments designed to monitor neurotransmitter release using synaptic phluorins. Finally, we applied SynEval to compare synaptic vesicle recycling evoked by electrical field stimulation and chemical depolarization in dissociated cortical cultures. Our data indicate that while the proportion of active synapses does not differ between stimulation modes, significantly more vesicles are mobilized upon chemical depolarization.
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Affiliation(s)
| | | | - Anna Fejtová
- *Correspondence: Anna Fejtová, ; Eva-Maria Weiss,
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50
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Jackson RE, Compans B, Burrone J. Correlative Live-Cell and Super-Resolution Imaging to Link Presynaptic Molecular Organisation With Function. Front Synaptic Neurosci 2022; 14:830583. [PMID: 35242024 PMCID: PMC8885727 DOI: 10.3389/fnsyn.2022.830583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/12/2022] [Indexed: 11/13/2022] Open
Abstract
Information transfer at synapses occurs when vesicles fuse with the plasma membrane to release neurotransmitters, which then bind to receptors at the postsynaptic membrane. The process of neurotransmitter release varies dramatically between different synapses, but little is known about how this heterogeneity emerges. The development of super-resolution microscopy has revealed that synaptic proteins are precisely organised within and between the two parts of the synapse and that this precise spatiotemporal organisation fine-tunes neurotransmission. However, it remains unclear if variability in release probability could be attributed to the nanoscale organisation of one or several proteins of the release machinery. To begin to address this question, we have developed a pipeline for correlative functional and super-resolution microscopy, taking advantage of recent technological advancements enabling multicolour imaging. Here we demonstrate the combination of live imaging of SypHy-RGECO, a unique dual reporter that simultaneously measures presynaptic calcium influx and neurotransmitter release, with post hoc immunolabelling and multicolour single molecule localisation microscopy, to investigate the structure-function relationship at individual presynaptic boutons.
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Affiliation(s)
- Rachel E. Jackson
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Benjamin Compans
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Juan Burrone
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
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