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Petkova-Tuffy A, Gödecke N, Viotti J, Korte M, Dresbach T. Neuroligin-1 mediates presynaptic maturation through brain-derived neurotrophic factor signaling. BMC Biol 2021; 19:215. [PMID: 34579720 PMCID: PMC8474808 DOI: 10.1186/s12915-021-01145-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 09/01/2021] [Indexed: 12/15/2022] Open
Abstract
Background Maturation is a process that allows synapses to acquire full functionality, optimizing their activity to diverse neural circuits, and defects in synaptic maturation may contribute to neurodevelopmental disorders. Neuroligin-1 (NL1) is a postsynaptic cell adhesion molecule essential for synapse maturation, a role typically attributed to binding to pre-synaptic ligands, the neurexins. However, the pathways underlying the action of NL1 in synaptic maturation are incompletely understood, and some of its previously observed effects seem reminiscent of those described for the neurotrophin brain-derived neurotrophic factor (BDNF). Here, we show that maturational increases in active zone stability and synaptic vesicle recycling rely on the joint action of NL1 and brain-derived neurotrophic factor (BDNF). Results Applying BDNF to hippocampal neurons in primary cultures or organotypical slice cultures mimicked the effects of overexpressing NL1 on both structural and functional maturation. Overexpressing a NL1 mutant deficient in neurexin binding still induced presynaptic maturation. Like NL1, BDNF increased synaptic vesicle recycling and the augmentation of transmitter release by phorbol esters, both hallmarks of presynaptic maturation. Mimicking the effects of NL1, BDNF also increased the half-life of the active zone marker bassoon at synapses, reflecting increased active zone stability. Overexpressing NL1 increased the expression and synaptic accumulation of BDNF. Inhibiting BDNF signaling pharmacologically or genetically prevented the effects of NL1 on presynaptic maturation. Applying BDNF to NL1-knockout mouse cultures rescued defective presynaptic maturation, indicating that BDNF acts downstream of NL1 and can restore presynaptic maturation at late stages of network development. Conclusions Our data introduce BDNF as a novel and essential component in a transsynaptic pathway linking NL1-mediated cell adhesion, neurotrophin action, and presynaptic maturation. Our findings connect synaptic cell adhesion and neurotrophin signaling and may provide a therapeutic approach to neurodevelopmental disorders by targeting synapse maturation. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01145-7.
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Affiliation(s)
- Andonia Petkova-Tuffy
- Institute for Anatomy and Embryology, University Medical Center Göttingen, Kreuzbergring 36, 37075, Göttingen, Germany
| | - Nina Gödecke
- Zoological Institute, Division of Cellular Neurobiology, TU Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Julio Viotti
- Institute for Anatomy and Embryology, University Medical Center Göttingen, Kreuzbergring 36, 37075, Göttingen, Germany
| | - Martin Korte
- Zoological Institute, Division of Cellular Neurobiology, TU Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany.,Helmholtz Centre for Infection Research, Research group Neuroinflammation and Neurodegeneration, Imhoffenstr. 7, 38104, Braunschweig, Germany
| | - Thomas Dresbach
- Institute for Anatomy and Embryology, University Medical Center Göttingen, Kreuzbergring 36, 37075, Göttingen, Germany.
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Okabe S. Recent advances in computational methods for measurement of dendritic spines imaged by light microscopy. Microscopy (Oxf) 2021; 69:196-213. [PMID: 32244257 DOI: 10.1093/jmicro/dfaa016] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 02/04/2020] [Accepted: 03/23/2020] [Indexed: 12/13/2022] Open
Abstract
Dendritic spines are small protrusions that receive most of the excitatory inputs to the pyramidal neurons in the neocortex and the hippocampus. Excitatory neural circuits in the neocortex and hippocampus are important for experience-dependent changes in brain functions, including postnatal sensory refinement and memory formation. Several lines of evidence indicate that synaptic efficacy is correlated with spine size and structure. Hence, precise and accurate measurement of spine morphology is important for evaluation of neural circuit function and plasticity. Recent advances in light microscopy and image analysis techniques have opened the way toward a full description of spine nanostructure. In addition, large datasets of spine nanostructure can be effectively analyzed using machine learning techniques and other mathematical approaches, and recent advances in super-resolution imaging allow researchers to analyze spine structure at an unprecedented level of precision. This review summarizes computational methods that can effectively identify, segment and quantitate dendritic spines in either 2D or 3D imaging. Nanoscale analysis of spine structure and dynamics, combined with new mathematical approaches, will facilitate our understanding of spine functions in physiological and pathological conditions.
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Affiliation(s)
- Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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Yamakawa M, Santosa SM, Chawla N, Ivakhnitskaia E, Del Pino M, Giakas S, Nadel A, Bontu S, Tambe A, Guo K, Han KY, Cortina MS, Yu C, Rosenblatt MI, Chang JH, Azar DT. Transgenic models for investigating the nervous system: Currently available neurofluorescent reporters and potential neuronal markers. Biochim Biophys Acta Gen Subj 2020; 1864:129595. [PMID: 32173376 DOI: 10.1016/j.bbagen.2020.129595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/24/2020] [Accepted: 03/03/2020] [Indexed: 02/06/2023]
Abstract
Recombinant DNA technologies have enabled the development of transgenic animal models for use in studying a myriad of diseases and biological states. By placing fluorescent reporters under the direct regulation of the promoter region of specific marker proteins, these models can localize and characterize very specific cell types. One important application of transgenic species is the study of the cytoarchitecture of the nervous system. Neurofluorescent reporters can be used to study the structural patterns of nerves in the central or peripheral nervous system in vivo, as well as phenomena involving embryologic or adult neurogenesis, injury, degeneration, and recovery. Furthermore, crucial molecular factors can also be screened via the transgenic approach, which may eventually play a major role in the development of therapeutic strategies against diseases like Alzheimer's or Parkinson's. This review describes currently available reporters and their uses in the literature as well as potential neural markers that can be leveraged to create additional, robust transgenic models for future studies.
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Affiliation(s)
- Michael Yamakawa
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Samuel M Santosa
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Neeraj Chawla
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Evguenia Ivakhnitskaia
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Matthew Del Pino
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Sebastian Giakas
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Arnold Nadel
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Sneha Bontu
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Arjun Tambe
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Kai Guo
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Kyu-Yeon Han
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Maria Soledad Cortina
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Charles Yu
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Mark I Rosenblatt
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Jin-Hong Chang
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America.
| | - Dimitri T Azar
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America.
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Okawa H, Yu WQ, Matti U, Schwarz K, Odermatt B, Zhong H, Tsukamoto Y, Lagnado L, Rieke F, Schmitz F, Wong ROL. Dynamic assembly of ribbon synapses and circuit maintenance in a vertebrate sensory system. Nat Commun 2019; 10:2167. [PMID: 31092821 PMCID: PMC6520400 DOI: 10.1038/s41467-019-10123-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 04/10/2019] [Indexed: 11/11/2022] Open
Abstract
Ribbon synapses transmit information in sensory systems, but their development is not well understood. To test the hypothesis that ribbon assembly stabilizes nascent synapses, we performed simultaneous time-lapse imaging of fluorescently-tagged ribbons in retinal cone bipolar cells (BCs) and postsynaptic densities (PSD95-FP) of retinal ganglion cells (RGCs). Ribbons and PSD95-FP clusters were more stable when these components colocalized at synapses. However, synapse density on ON-alpha RGCs was unchanged in mice lacking ribbons (ribeye knockout). Wildtype BCs make both ribbon-containing and ribbon-free synapses with these GCs even at maturity. Ribbon assembly and cone BC-RGC synapse maintenance are thus regulated independently. Despite the absence of synaptic ribbons, RGCs continued to respond robustly to light stimuli, although quantitative examination of the responses revealed reduced frequency and contrast sensitivity.
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Affiliation(s)
- Haruhisa Okawa
- Department of Biological Structure, University of Washington, Seattle, 98195, WA, USA
| | - Wan-Qing Yu
- Department of Biological Structure, University of Washington, Seattle, 98195, WA, USA
| | - Ulf Matti
- Department of Neuroanatomy, Medical School Homburg/Saar, Institute for Anatomy and Cell Biology, Saarland University, Homburg/Saar, 66421, Germany
| | - Karin Schwarz
- Department of Neuroanatomy, Medical School Homburg/Saar, Institute for Anatomy and Cell Biology, Saarland University, Homburg/Saar, 66421, Germany
| | | | - Haining Zhong
- Vollum institute, Oregon Health and Science University, Portland, 97239, OR, USA
| | - Yoshihiko Tsukamoto
- Department of Biology, Hyogo College of Medicine, Nishinomiya, 663-8501, Hyogo, Japan
| | - Leon Lagnado
- School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Fred Rieke
- Department of Physiology and Biophysics, University of Washington, Seattle, 98195, WA, USA
| | - Frank Schmitz
- Department of Neuroanatomy, Medical School Homburg/Saar, Institute for Anatomy and Cell Biology, Saarland University, Homburg/Saar, 66421, Germany
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, Seattle, 98195, WA, USA.
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Sato Y, Okabe S. Nano-scale analysis of synapse morphology in an autism mouse model with 15q11-13 copy number variation using focused ion beam milling and scanning electron microscopy. Microscopy (Oxf) 2019; 68:122-132. [PMID: 30371805 DOI: 10.1093/jmicro/dfy128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/26/2018] [Accepted: 10/09/2018] [Indexed: 02/07/2023] Open
Abstract
Circuit-level alternations in patients of autism spectrum disorder (ASD) is under active investigation and detailed characterization of synapse morphology in ASD model mice should be informative. We utilized focused ion beam milling and scanning electron microscopy (FIB-SEM) to obtain three-dimensional images of synapses in the layer 2/3 of the somatosensory cortex from a mouse model for ASD with human 15q11-13 chromosomal duplication (15q dup mice). We found a trend of higher spine density and a higher fraction of astrocytic contact with both spine and shaft synapses in 15q dup mice. Measurement of spine synapse structure indicated that the size of the post-synaptic density (PSD), spine head volume, spine head width and spine neck width were smaller in 15q dup mice. Categorization of spine synapses into five classes suggested a trend of less frequent mushroom spines in 15q dup mice. These results suggest relative increase in excitatory synapses with immature morphology but more astrocytic contacts in 15q dup mice, which may be linked to enhanced synapse turnover seen in ASD mouse models.
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Affiliation(s)
- Yuka Sato
- Department of Cellular Neurobiology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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