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Velica A, Kullander K. A flowchart for adequate controls in virus-based monosynaptic tracing experiments identified Cre-independent leakage of the TVA receptor in RΦGT mice. BMC Neurosci 2024; 25:9. [PMID: 38383317 PMCID: PMC10882902 DOI: 10.1186/s12868-024-00848-1] [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: 12/07/2023] [Accepted: 01/29/2024] [Indexed: 02/23/2024] Open
Abstract
BACKGROUND A pseudotyped modified rabies virus lacking the rabies glycoprotein (G-protein), which is crucial for transsynaptic spread, can be used for monosynaptic retrograde tracing. By coupling the pseudotyped virus with transgene expression of the G-protein and the avian leukosis and sarcoma virus subgroup A receptor (TVA), which is necessary for cell entry of the virus, researchers can investigate specific neuronal populations. Responder mouse lines, like the RΦGT mouse line, carry the genes encoding the G-protein and TVA under Cre-dependent expression. These mouse lines are valuable tools because they reduce the number of viral injections needed compared to when using helper viruses. Since RΦGT mice do not express Cre themselves, introducing the pseudotyped rabies virus into their brain should not result in viral cell entry or spread. RESULTS We present a straightforward flowchart for adequate controls in tracing experiments, which we employed to demonstrate Cre-independent expression of TVA in RΦGT mice. CONCLUSIONS Our observations revealed TVA leakage, indicating that RΦGT mice should be used with caution for transgene expression of TVA. Inaccurate tracing outcomes may occur if TVA is expressed in the absence of Cre since background leakage leads to nonspecific cell entry. Moreover, conducting appropriate control experiments can identify the source of potential caveats in virus-based neuronal tracing experiments.
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Affiliation(s)
- Anna Velica
- Department of Immunology, Genetics and Pathology, Uppsala University, 815, Husargatan 3, Uppsala, 751 08, Sweden.
| | - Klas Kullander
- Department of Immunology, Genetics and Pathology, Uppsala University, 815, Husargatan 3, Uppsala, 751 08, Sweden
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Wolterhoff N, Hiesinger PR. Synaptic promiscuity in brain development. Curr Biol 2024; 34:R102-R116. [PMID: 38320473 PMCID: PMC10849093 DOI: 10.1016/j.cub.2023.12.037] [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: 02/08/2024]
Abstract
Precise synaptic connectivity is a prerequisite for the function of neural circuits, yet individual neurons, taken out of their developmental context, readily form unspecific synapses. How does the genome encode brain wiring in light of this apparent contradiction? Synaptic specificity is the outcome of a long series of developmental processes and mechanisms before, during and after synapse formation. How much promiscuity is permissible or necessary at the moment of synaptic partner choice depends on the extent to which prior development restricts available partners or subsequent development corrects initially made synapses. Synaptic promiscuity at the moment of choice can thereby play important roles in the development of precise connectivity, but also facilitate developmental flexibility and robustness. In this review, we assess the experimental evidence for the prevalence and roles of promiscuous synapse formation during brain development. Many well-established experimental approaches are based on developmental genetic perturbation and an assessment of synaptic connectivity only in the adult; this can make it difficult to pinpoint when a given defect or mechanism occurred. In many cases, such studies reveal mechanisms that restrict partner availability already prior to synapse formation. Subsequently, at the moment of choice, factors including synaptic competency, interaction dynamics and molecular recognition further restrict synaptic partners. The discussion of the development of synaptic specificity through the lens of synaptic promiscuity suggests an algorithmic process based on neurons capable of promiscuous synapse formation that are continuously prevented from making the wrong choices, with no single mechanism or developmental time point sufficient to explain the outcome.
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Affiliation(s)
- Neele Wolterhoff
- Division of Neurobiology, Free University Berlin, 14195 Berlin, Germany
| | - P Robin Hiesinger
- Division of Neurobiology, Free University Berlin, 14195 Berlin, Germany.
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Matcham AC, Toma K, Tsai NY, Sze CJ, Lin PY, Stewart IF, Duan X. Cadherin-13 Maintains Retinotectal Synapses via Transneuronal Interactions. J Neurosci 2024; 44:e1310232023. [PMID: 38123991 PMCID: PMC10860569 DOI: 10.1523/jneurosci.1310-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 12/03/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Maintaining precise synaptic contacts between neuronal partners is critical to ensure the proper functioning of the mammalian central nervous system (CNS). Diverse cell recognition molecules, such as classic cadherins (Cdhs), are part of the molecular machinery mediating synaptic choices during development and synaptic maintenance. Yet, the principles governing neuron-neuron wiring across diverse CNS neuron types remain largely unknown. The retinotectal synapses, connections from the retinal ganglion cells (RGCs) to the superior collicular (SC) neurons, offer an ideal experimental system to reveal molecular logic underlying synaptic choices and formation. This is due to the retina's unidirectional and laminar-restricted projections to the SC and the large databases of presynaptic RGC subtypes and postsynaptic SC neuronal types. Here, we focused on determining the role of Type II Cdhs in wiring the retinotectal synapses. We surveyed Cdhs expression patterns at neuronal resolution and revealed that Cdh13 is enriched in the wide-field neurons in the superficial SC (sSC). In either the Cdh13 null mutant or selective adult deletion within the wide-field neurons, there is a significant reduction of spine densities in the distal dendrites of these neurons in both sexes. Additionally, Cdh13 removal from presynaptic RGCs reduced dendritic spines in the postsynaptic wide-field neurons. Cdh13-expressing RGCs use differential mechanisms than αRGCs and On-Off Direction-Selective Ganglion Cells (ooDSGCs) to form specific retinotectal synapses. The results revealed a selective transneuronal interaction mediated by Cdh13 to maintain proper retinotectal synapses in vivo.
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Affiliation(s)
- Angela C Matcham
- Neuroscience Graduate Program, Department of Ophthalmology, Kavli Institute for Fundamental Neuroscience, University of California SanFrancisco, San Francisco 94143-2811, California
| | - Kenichi Toma
- Neuroscience Graduate Program, Department of Ophthalmology, Kavli Institute for Fundamental Neuroscience, University of California SanFrancisco, San Francisco 94143-2811, California
| | - Nicole Y Tsai
- Neuroscience Graduate Program, Department of Ophthalmology, Kavli Institute for Fundamental Neuroscience, University of California SanFrancisco, San Francisco 94143-2811, California
| | - Christina J Sze
- Neuroscience Graduate Program, Department of Ophthalmology, Kavli Institute for Fundamental Neuroscience, University of California SanFrancisco, San Francisco 94143-2811, California
| | - Pin-Yeh Lin
- Neuroscience Graduate Program, Department of Ophthalmology, Kavli Institute for Fundamental Neuroscience, University of California SanFrancisco, San Francisco 94143-2811, California
| | - Ilaria F Stewart
- Neuroscience Graduate Program, Department of Ophthalmology, Kavli Institute for Fundamental Neuroscience, University of California SanFrancisco, San Francisco 94143-2811, California
| | - Xin Duan
- Neuroscience Graduate Program, Department of Ophthalmology, Kavli Institute for Fundamental Neuroscience, University of California SanFrancisco, San Francisco 94143-2811, California
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Tan CX, Bindu DS, Hardin EJ, Sakers K, Baumert R, Ramirez JJ, Savage JT, Eroglu C. δ-Catenin controls astrocyte morphogenesis via layer-specific astrocyte-neuron cadherin interactions. J Cell Biol 2023; 222:e202303138. [PMID: 37707499 PMCID: PMC10501387 DOI: 10.1083/jcb.202303138] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/14/2023] [Accepted: 08/28/2023] [Indexed: 09/15/2023] Open
Abstract
Astrocytes control the formation of specific synaptic circuits via cell adhesion and secreted molecules. Astrocyte synaptogenic functions are dependent on the establishment of their complex morphology. However, it is unknown if distinct neuronal cues differentially regulate astrocyte morphogenesis. δ-Catenin was previously thought to be a neuron-specific protein that regulates dendrite morphology. We found δ-catenin is also highly expressed by astrocytes and required both in astrocytes and neurons for astrocyte morphogenesis. δ-Catenin is hypothesized to mediate transcellular interactions through the cadherin family of cell adhesion proteins. We used structural modeling and biochemical analyses to reveal that δ-catenin interacts with the N-cadherin juxtamembrane domain to promote N-cadherin surface expression. An autism-linked δ-catenin point mutation impaired N-cadherin cell surface expression and reduced astrocyte complexity. In the developing mouse cortex, only lower-layer cortical neurons express N-cadherin. Remarkably, when we silenced astrocytic N-cadherin throughout the cortex, only lower-layer astrocyte morphology was disrupted. These findings show that δ-catenin controls astrocyte-neuron cadherin interactions that regulate layer-specific astrocyte morphogenesis.
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Affiliation(s)
- Christabel Xin Tan
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | | | - Evelyn J. Hardin
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Kristina Sakers
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Ryan Baumert
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Juan J. Ramirez
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
| | - Justin T. Savage
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
- Howard Hughes Medical Institute, Duke University School of Medicine, Durham, NC, USA
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Mesías RE, Zaki Y, Guevara CA, Friedman LG, Hussein A, Therrien K, Magee AR, Tzavaras N, Del Valle P, Baxter MG, Huntley GW, Benson DL. Development and cadherin-mediated control of prefrontal corticostriatal projections in mice. iScience 2023; 26:108002. [PMID: 37854688 PMCID: PMC10579443 DOI: 10.1016/j.isci.2023.108002] [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: 03/21/2023] [Revised: 08/07/2023] [Accepted: 09/18/2023] [Indexed: 10/20/2023] Open
Abstract
Action-outcome associations depend on prefrontal cortex (PFC) projections to the dorsal striatum. To assess how these projections form, we measured PFC axon patterning, synapse formation, and functional maturation in the postnatally developing mouse striatum. Using Hotspot analysis, we show that PFC axons form an adult-like pattern of clustered terminations in the first postnatal week that remains largely stable thereafter. PFC-striatal synaptic strength is adult-like by P21, while excitatory synapse density increases until adulthood. We then tested how the targeted deletion of a candidate adhesion/guidance protein, Cadherin-8 (Cdh8), from corticostriatal neurons regulates pathway development. Mutant mice showed diminished PFC axon targeting and reduced spontaneous glutamatergic synaptic activity in the dorsal striatum. They also exhibited impaired behavioral performance in action-outcome learning. The data show that PFC-striatal axons form striatal territories through an early, directed growth model and they highlight essential contributions of Cdh8 to the anatomical and functional features critical for the formation of action-outcome associations.
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Affiliation(s)
- Roxana E. Mesías
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yosif Zaki
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Christopher A. Guevara
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Lauren G. Friedman
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ayan Hussein
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Karen Therrien
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Alexandra R. Magee
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Nikolaos Tzavaras
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Pamela Del Valle
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mark G. Baxter
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Section on Comparative Medicine, Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - George W. Huntley
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Deanna L. Benson
- Nash Family Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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Mesías RE, Zaki Y, Guevara CA, Friedman LG, Hussein A, Therrien K, Magee AR, Tzavaras N, Valle PD, Baxter MG, Huntley GW, Benson DL. Development of prefrontal corticostriatal connectivity in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532475. [PMID: 36993639 PMCID: PMC10054964 DOI: 10.1101/2023.03.14.532475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Rational decision making is grounded in learning to associate actions with outcomes, a process that depends on projections from prefrontal cortex to dorsomedial striatum. Symptoms associated with a variety of human pathological conditions ranging from schizophrenia and autism to Huntington's and Parkinson's disease point toward functional deficits in this projection, but its development is not well understood, making it difficult to investigate how perturbations in development of this circuitry could contribute to pathophysiology. We applied a novel strategy based on Hotspot Analysis to assess the developmental progression of anatomical positioning of prefrontal cortex to striatal projections. Corticostriatal axonal territories established at P7 expand in concert with striatal growth but remain largely unchanged in positioning through adulthood, indicating they are generated by directed, targeted growth and not modified extensively by postnatal experience. Consistent with these findings, corticostriatal synaptogenesis increased steadily from P7 to P56, with no evidence for widescale pruning. As corticostriatal synapse density increased over late postnatal ages, the strength of evoked PFC input onto dorsomedial striatal projection neurons also increased, but spontaneous glutamatergic synaptic activity was stable. Based on its pattern of expression, we asked whether the adhesion protein, Cdh8, influenced this progression. In mice lacking Cdh8 in PFC corticostriatal projection neurons, axon terminal fields in dorsal striatum shifted ventrally. Corticostriatal synaptogenesis was unimpeded, but spontaneous EPSC frequency declined and mice failed to learn to associate an action with an outcome. Collectively these findings show that corticostriatal axons grow to their target zone and are restrained from an early age, do not undergo postnatal synapse pruning as the most dominant models predict, and that a relatively modest shift in terminal arbor positioning and synapse function has an outsized, negative impact on corticostriatal-dependent behavior.
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Vagnozzi AN, Moore MT, López de Boer R, Agarwal A, Zampieri N, Landmesser LT, Philippidou P. Catenin signaling controls phrenic motor neuron development and function during a narrow temporal window. Front Neural Circuits 2023; 17:1121049. [PMID: 36895798 PMCID: PMC9988953 DOI: 10.3389/fncir.2023.1121049] [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: 12/11/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
Phrenic Motor Column (PMC) neurons are a specialized subset of motor neurons (MNs) that provide the only motor innervation to the diaphragm muscle and are therefore essential for survival. Despite their critical role, the mechanisms that control phrenic MN development and function are not well understood. Here, we show that catenin-mediated cadherin adhesive function is required for multiple aspects of phrenic MN development. Deletion of β- and γ-catenin from MN progenitors results in perinatal lethality and a severe reduction in phrenic MN bursting activity. In the absence of catenin signaling, phrenic MN topography is eroded, MN clustering is lost and phrenic axons and dendrites fail to grow appropriately. Despite the essential requirement for catenins in early phrenic MN development, they appear to be dispensable for phrenic MN maintenance, as catenin deletion from postmitotic MNs does not impact phrenic MN topography or function. Our data reveal a fundamental role for catenins in PMC development and suggest that distinct mechanisms are likely to control PMC maintenance.
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Affiliation(s)
- Alicia N. Vagnozzi
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
| | - Matthew T. Moore
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
| | - Raquel López de Boer
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
| | - Aambar Agarwal
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
| | - Niccolò Zampieri
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Lynn T. Landmesser
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
| | - Polyxeni Philippidou
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
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