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Koch S, Kandimalla P, Padilla E, Kaur S, Kaur R, Nguyen M, Nelson A, Khalsa S, Younossi-Hartenstein A, Hartenstein V. Structural changes shaping the Drosophila ellipsoid body ER-neurons during development and aging. Dev Biol 2024; 516:96-113. [PMID: 39089472 DOI: 10.1016/j.ydbio.2024.07.018] [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: 02/23/2024] [Revised: 07/25/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024]
Abstract
The ellipsoid body (EB) of the insect brain performs pivotal functions in controlling navigation. Input and output of the EB is provided by multiple classes of R-neurons (now referred to as ER-neurons) and columnar neurons which interact with each other in a stereotypical and spatially highly ordered manner. The developmental mechanisms that control the connectivity and topography of EB neurons are largely unknown. One indispensable prerequisite to unravel these mechanisms is to document in detail the sequence of events that shape EB neurons during their development. In this study, we analyzed the development of the Drosophila EB. In addition to globally following the ER-neuron and columnar neuron (sub)classes in the spatial context of their changing environment we performed a single cell analysis using the multi-color flip out (MCFO) system to analyze the developmental trajectory of ER-neurons at different pupal stages, young adults (4d) and aged adults (∼60d). We show that the EB develops as a merger of two distinct elements, a posterior and anterior EB primordium (prEBp and prEBa, respectively. ER-neurons belonging to different subclasses form growth cones and filopodia that associate with the prEBp and prEBa in a pattern that, from early pupal stages onward, foreshadows their mature structure. Filopodia of all ER-subclasses are initially much longer than the dendritic and terminal axonal branches they give rise to, and are pruned back during late pupal stages. Interestingly, extraneous branches, particularly significant in the dendritic domain, are a hallmark of ER-neuron structure in aged brains. Aging is also associated with a decline in synaptic connectivity from columnar neurons, as well as upregulation of presynaptic protein (Brp) in ER-neurons. Our findings advance the EB (and ER-neurons) as a favorable system to visualize and quantify the development and age-related decline of a complex neuronal circuitry.
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Affiliation(s)
- Sandra Koch
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Pratyush Kandimalla
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Eddie Padilla
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Sabrina Kaur
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Rabina Kaur
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - My Nguyen
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Annie Nelson
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Satkartar Khalsa
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Amelia Younossi-Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA.
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2
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Hashimoto J, Fujita E, Tanimoto K, Kondo S, Matsumoto-Miyai K. Effects of Cardiac Glycoside Digoxin on Dendritic Spines and Motor Learning Performance in Mice. Neuroscience 2024; 541:77-90. [PMID: 38278474 DOI: 10.1016/j.neuroscience.2024.01.018] [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: 06/01/2023] [Revised: 01/17/2024] [Accepted: 01/22/2024] [Indexed: 01/28/2024]
Abstract
Synapse formation following the generation of postsynaptic dendritic spines is essential for motor learning and functional recovery after brain injury. The C-terminal fragment of agrin cleaved by neurotrypsin induces dendritic spine formation in the adult hippocampus. Since the α3 subunit of sodium-potassium ATPase (Na/K ATPase) is a neuronal receptor for agrin in the central nervous system, cardiac glycosides might facilitate dendritic spine formation and subsequent improvements in learning. This study investigated the effects of cardiac glycoside digoxin on dendritic spine turnover and learning performance in mice. Golgi-Cox staining revealed that intraperitoneal injection of digoxin less than its IC50 in the brain significantly increased the density of long spines (≥2 µm) in the cerebral cortex in wild-type mice and neurotrypsin-knockout (NT-KO) mice showing impairment of activity-dependent spine formation. Although the motor learning performance of NT-KO mice was significantly lower than control wild-type mice under the control condition, low doses of digoxin enhanced performance to a similar degree in both strains. In NT-KO mice, lower digoxin doses equivalent to clinical doses also significantly improved motor learning performance. These data suggest that lower doses of digoxin could modify dendritic spine formation or recycling and facilitate motor learning in compensation for the disruption of neurotrypsin-agrin pathway.
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Affiliation(s)
- Junichi Hashimoto
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Erika Fujita
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Keisuke Tanimoto
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Suzuo Kondo
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan
| | - Kazumasa Matsumoto-Miyai
- Graduate School of Rehabilitation Science, Osaka Metropolitan University, 3-7-30 Habikino, Habikino-City, Osaka 583-8555, Japan.
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3
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Nemoz-Billet L, Brocard J, Ruggiero F, Bretaud S. Quantitative Image Analysis of Axonal Morphology in In Vivo Model. Methods Protoc 2023; 6:116. [PMID: 38133136 PMCID: PMC10745806 DOI: 10.3390/mps6060116] [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: 10/12/2023] [Revised: 11/14/2023] [Accepted: 11/16/2023] [Indexed: 12/23/2023] Open
Abstract
Quantifying axonal branching is crucial for understanding neural circuit function, developmental and regeneration processes and disease mechanisms. Factors that regulate patterns of axonal arborization and tune neuronal circuits are investigated for their implication in various disorders in brain connectivity. The lack of a reliable and user-friendly method makes the quantitative analysis of axon morphology difficult. Specifically, methods to visualize and quantify the complex axon arborization are challenging to implement and apply practically. Our study was aimed at developing a robust but simple method of quantification that used ImageJ 2D analysis and compared it with Imaris visualization and analysis of 3D images. We used zebrafish fluorescent transgenic lines to perform in vivo imaging of developing motor neuron axons that adequately reflected the complexity of axonal networks. Our new method, developed on ImageJ, is easy and fast, giving access to new information such as collateral distribution along the axonal shaft. This study describes step-by-step procedures that can be easily applied to a variety of organisms and in vitro systems. Our study provides a basis for further exploration of neural circuits to gain new insights into neuronal disorders and potential therapeutic interventions.
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Affiliation(s)
- Laurie Nemoz-Billet
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, UMR5242 CNRS, Université Claude Bernard-Lyon-1, 69364 Lyon, France; (L.N.-B.); (F.R.)
| | - Jacques Brocard
- PLATIM, SFR Biosciences, ENS de Lyon, Inserm US8, CNRS UMS3444, Université Claude Bernard-Lyon-1, 69364 Lyon, France;
| | - Florence Ruggiero
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, UMR5242 CNRS, Université Claude Bernard-Lyon-1, 69364 Lyon, France; (L.N.-B.); (F.R.)
| | - Sandrine Bretaud
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, UMR5242 CNRS, Université Claude Bernard-Lyon-1, 69364 Lyon, France; (L.N.-B.); (F.R.)
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4
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Dutta SB, Linneweber GA, Andriatsilavo M, Hiesinger PR, Hassan BA. EGFR-dependent suppression of synaptic autophagy is required for neuronal circuit development. Curr Biol 2023; 33:517-532.e5. [PMID: 36640763 DOI: 10.1016/j.cub.2022.12.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 10/31/2022] [Accepted: 12/14/2022] [Indexed: 01/15/2023]
Abstract
The development of neuronal connectivity requires stabilization of dynamic axonal branches at sites of synapse formation. Models that explain how axonal branching is coupled to synaptogenesis postulate molecular regulators acting in a spatiotemporally restricted fashion to ensure branching toward future synaptic partners while also stabilizing the emerging synaptic contacts between such partners. We investigated this question using neuronal circuit development in the Drosophila brain as a model system. We report that epidermal growth factor receptor (EGFR) activity is required in presynaptic axonal branches during two distinct temporal intervals to regulate circuit wiring in the developing Drosophila visual system. EGFR is required early to regulate primary axonal branching. EGFR activity is then independently required at a later stage to prevent degradation of the synaptic active zone protein Bruchpilot (Brp). Inactivation of EGFR results in a local increase of autophagy in presynaptic branches and the translocation of active zone proteins into autophagic vesicles. The protection of synaptic material during this later interval of wiring ensures the stabilization of terminal branches, circuit connectivity, and appropriate visual behavior. Phenotypes of EGFR inactivation can be rescued by increasing Brp levels or downregulating autophagy. In summary, we identify a temporally restricted molecular mechanism required for coupling axonal branching and synaptic stabilization that contributes to the emergence of neuronal wiring specificity.
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Affiliation(s)
- Suchetana B Dutta
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany
| | | | - Maheva Andriatsilavo
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany
| | | | - Bassem A Hassan
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany.
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5
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Wit CB, Hiesinger PR. Neuronal filopodia: From stochastic dynamics to robustness of brain morphogenesis. Semin Cell Dev Biol 2023; 133:10-19. [PMID: 35397971 DOI: 10.1016/j.semcdb.2022.03.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 03/26/2022] [Accepted: 03/29/2022] [Indexed: 12/30/2022]
Abstract
Brain development relies on dynamic morphogenesis and interactions of neurons. Filopodia are thin and highly dynamic membrane protrusions that are critically required for neuronal development and neuronal interactions with the environment. Filopodial interactions are typically characterized by non-deterministic dynamics, yet their involvement in developmental processes leads to stereotypic and robust outcomes. Here, we discuss recent advances in our understanding of how filopodial dynamics contribute to neuronal differentiation, migration, axonal and dendritic growth and synapse formation. Many of these advances are brought about by improved methods of live observation in intact developing brains. Recent findings integrate known and novel roles ranging from exploratory sensors and decision-making agents to pools for selection and mechanical functions. Different types of filopodial dynamics thereby reveal non-deterministic subcellular decision-making processes as part of genetically encoded brain development.
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Affiliation(s)
- Charlotte B Wit
- Devision of Neurobiology, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - P Robin Hiesinger
- Devision of Neurobiology, Institute of Biology, Freie Universität Berlin, Berlin, Germany.
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6
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Weber JJ, Brummett LM, Coca ME, Tabunoki H, Kanost MR, Ragan EJ, Park Y, Gorman MJ. Phenotypic analyses, protein localization, and bacteriostatic activity of Drosophila melanogaster transferrin-1. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 147:103811. [PMID: 35781032 PMCID: PMC9869689 DOI: 10.1016/j.ibmb.2022.103811] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
Transferrin-1 (Tsf1) is an extracellular insect protein with a high affinity for iron. The functions of Tsf1 are still poorly understood; however, Drosophila melanogaster Tsf1 has been shown to influence iron distribution in the fly body and to protect flies against some infections. The goal of this study was to better understand the physiological functions of Tsf1 in D. melanogaster by 1) investigating Tsf1 null phenotypes, 2) determining tissue-specific localization of Tsf1, 3) measuring the concentration of Tsf1 in hemolymph, 4) testing Tsf1 for bacteriostatic activity, and 5) evaluating the effect of metal and paraquat treatments on Tsf1 abundance. Flies lacking Tsf1 had more iron than wild-type flies in specialized midgut cells that take up iron from the diet; however, the absence of Tsf1 had no effect on the iron content of whole midguts, fat body, hemolymph, or heads. Thus, as previous studies have suggested, Tsf1 appears to have a minor role in iron transport. Tsf1 was abundant in hemolymph from larvae (0.4 μM), pupae (1.4 μM), adult females (4.4 μM) and adult males (22 μM). Apo-Tsf1 at 1 μM had bacteriostatic activity whereas holo-Tsf1 did not, suggesting that Tsf1 can inhibit microbial growth by sequestering iron in hemolymph and other extracellular environments. This hypothesis was supported by detection of secreted Tsf1 in tracheae, testes and seminal vesicles. Colocalization of Tsf1 with an endosome marker in oocytes suggested that Tsf1 may provide iron to developing eggs; however, eggs from mothers lacking Tsf1 had the same amount of iron as control eggs, and they hatched at a wild-type rate. Thus, the primary function of Tsf1 uptake by oocytes may be to defend against infection rather than to provide eggs with iron. In beetles, Tsf1 plays a role in protection against oxidative stress. In contrast, we found that flies lacking Tsf1 had a typical life span and greater resistance to paraquat-induced oxidative stress. In addition, Tsf1 abundance remained unchanged in response to ingestion of iron, cadmium or paraquat or to injection of iron. These results suggest that Tsf1 has a limited role in protection against oxidative stress in D. melanogaster.
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Affiliation(s)
- Jacob J Weber
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA.
| | - Lisa M Brummett
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA.
| | - Michelle E Coca
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA.
| | - Hiroko Tabunoki
- Department of Science of Biological Production, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan.
| | - Michael R Kanost
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA.
| | - Emily J Ragan
- Department of Chemistry and Biochemistry, Metropolitan State University of Denver, Denver, CO, 80217, USA.
| | - Yoonseong Park
- Department of Entomology, Kansas State University, Manhattan, KS, 66506, USA.
| | - Maureen J Gorman
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA.
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7
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Voelzmann A, Sanchez-Soriano N. Drosophila Primary Neuronal Cultures as a Useful Cellular Model to Study and Image Axonal Transport. Methods Mol Biol 2022; 2431:429-449. [PMID: 35412291 DOI: 10.1007/978-1-0716-1990-2_23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The use of primary neuronal cultures generated from Drosophila tissue provides a powerful model for studies of transport mechanisms. Cultured fly neurons provide similarly detailed subcellular resolution and applicability of pharmacology or fluorescent dyes as mammalian primary neurons. As an experimental advantage for the mechanistic dissection of transport, fly primary neurons can be combined with the fast and highly efficient combinatorial genetics of Drosophila, and genetic tools for the manipulation of virtually every fly gene are readily available. This strategy can be performed in parallel to in vivo transport studies to address relevance of any findings. Here we will describe the generation of primary neuronal cultures from Drosophila embryos and larvae, the use of external fluorescent dyes and genetic tools to label cargo, and the key strategies for live imaging and subsequent analysis.
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Affiliation(s)
- André Voelzmann
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
| | - Natalia Sanchez-Soriano
- Department of Molecular Physiology & Cell Signalling, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool, UK.
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8
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Kobayashi Y, Oguro A, Yagi E, Mitani A, Kudoh SN, Imaoka S. Bisphenol A and rotenone induce S-nitrosylation of protein disulfide isomerase (PDI) and inhibit neurite outgrowth of primary cultured cells of the rat hippocampus and PC12 cells. J Toxicol Sci 2021; 45:783-794. [PMID: 33268678 DOI: 10.2131/jts.45.783] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Bisphenol A (BPA) interferes the function and development of the central nervous system (CNS), resulting in behavioral abnormalities and memory loss. S-nitrosylation of protein disulfide isomerase (PDI) is increased in brains with sporadic Alzheimer's disease and Parkinson's disease. The aim of the present study was to clarify the role of nitric oxide (NO) in BPA-induced neurotoxicity. Since rotenone induces NO-mediated neurodegeneration through S-nitrosylation of PDI, it was used as a positive control. First, rats were treated with BPA and rotenone, and S-nitrosylation of PDI was detected in rat brain microsomes. BPA and rotenone decreased RNase oxidation activity of PDI concomitant with S-nitrosylation of PDI. Next, to clarify S-nitrosylation of PDI by BPA and rotenone in rat brains, we treated the rat pheochromocytoma cell line PC12 and primary cultured neuron cells from the rat hippocampus with BPA (5 and 10 μM) and rotenone (100 or 200 nM). BPA induced S-nitrosylation of PDI, while NG-monomethyl-L-arginine (L-NMMA), a NOS inhibitor, exerted the opposite effects. Finally, to evaluate the toxicity of BPA in the CNS, we investigated its effects on neurite outgrowth of PC12 and primary cultured neuron cells. BPA inhibited neurite outgrowth of these cells, while L-NMMA reversed this inhibition. The involvement of PDI activity in neurite outgrowth was also examined, and bacitracin, a PDI inhibitor, is shown to decrease neurite outgrowth. Furthermore, the overexpression of PDI, but not a catalytically inactive PDI mutant, enhanced neurite outgrowth. These results suggested that S-nitrosylation of PDI induced by excessive NO caused BPA-induced neurotoxicity.
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Affiliation(s)
- Yukino Kobayashi
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University
| | - Ami Oguro
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University.,Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University
| | - Erina Yagi
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University
| | - Akira Mitani
- Department of Human-System Interaction, School of Science and Technology, Kwansei Gakuin University
| | - Suguru N Kudoh
- Department of Human-System Interaction, School of Science and Technology, Kwansei Gakuin University
| | - Susumu Imaoka
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University
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9
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Hiesinger PR. Brain wiring with composite instructions. Bioessays 2020; 43:e2000166. [PMID: 33145823 DOI: 10.1002/bies.202000166] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/27/2020] [Accepted: 09/29/2020] [Indexed: 11/12/2022]
Abstract
The quest for molecular mechanisms that guide axons or specify synaptic contacts has largely focused on molecules that intuitively relate to the idea of an "instruction." By contrast, "permissive" factors are traditionally considered background machinery without contribution to the information content of a molecularly executed instruction. In this essay, I recast this dichotomy as a continuum from permissive to instructive actions of single factors that provide relative contributions to a necessarily collaborative effort. Individual molecules or other factors do not constitute absolute instructions by themselves; they provide necessary context for each other, thereby creating a composite that defines the overall instruction. The idea of composite instructions leads to two main conclusions: first, a composite of many seemingly permissive factors can define a specific instruction even in the absence of a single dominant contributor; second, individual factors are not necessarily related intuitively to the overall instruction or phenotypic outcome.
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Affiliation(s)
- P Robin Hiesinger
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
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10
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Andriatsilavo M, Hassan B. [When brain development shapes individual behavior]. Med Sci (Paris) 2020; 36:714-716. [PMID: 32821047 DOI: 10.1051/medsci/2020144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mahéva Andriatsilavo
- Institut du cerveau et de la moelle épinière (ICM) - Sorbonne Université, Inserm, CNRS, Hôpital Pitié-Salpêtrière, 47 boulevard de l'Hôpital, 75013 Paris, France - Division of neurobiology of the Institute for biology, Free university, Königin-Luise-Str. 1-3, DE 14195 Berlin, Allemagne - Einstein-BIH, Charité Universitätsmedizin, Berlin, Allemagne
| | - Bassem Hassan
- Institut du cerveau et de la moelle épinière (ICM) - Sorbonne Université, Inserm, CNRS, Hôpital Pitié-Salpêtrière, 47 boulevard de l'Hôpital, 75013 Paris, France - Division of neurobiology of the Institute for biology, Free university, Königin-Luise-Str. 1-3, DE 14195 Berlin, Allemagne - Einstein-BIH, Charité Universitätsmedizin, Berlin, Allemagne
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11
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Al-Mubarak BR, Omar A, Baz B, Al-Abdulaziz B, Magrashi AI, Al-Yemni E, Jabaan A, Monies D, Abouelhoda M, Abebe D, Ghaziuddin M, Al-Tassan NA. Whole exome sequencing in ADHD trios from single and multi-incident families implicates new candidate genes and highlights polygenic transmission. Eur J Hum Genet 2020; 28:1098-1110. [PMID: 32238911 PMCID: PMC7382449 DOI: 10.1038/s41431-020-0619-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 02/26/2020] [Accepted: 03/10/2020] [Indexed: 12/18/2022] Open
Abstract
Several types of genetic alterations occurring at numerous loci have been described in attention deficit hyperactivity disorder (ADHD). However, the role of rare single nucleotide variants (SNVs) remains under investigated. Here, we sought to identify rare SNVs with predicted deleterious effect that may contribute to ADHD risk. We chose to study ADHD families (including multi-incident) from a population with a high rate of consanguinity in which genetic risk factors tend to accumulate and therefore increasing the chance of detecting risk alleles. We employed whole exome sequencing (WES) to interrogate the entire coding region of 16 trios with ADHD. We also performed enrichment analysis on our final list of genes to identify the overrepresented biological processes. A total of 32 rare variants with predicted damaging effect were identified in 31 genes. At least two variants were detected per proband, most of which were not exclusive to the affected individuals. In addition, the majority of our candidate genes have not been previously described in ADHD including five genes (NEK4, NLE1, PSRC1, PTP4A3, and TMEM183A) that were not previously described in any human condition. Moreover, enrichment analysis highlighted brain-relevant biological themes such as "Glutamatergic synapse", "Cytoskeleton organization", and "Ca2+ pathway". In conclusion, our findings are in keeping with prior studies demonstrating the highly challenging genetic architecture of ADHD involving low penetrance, variable expressivity and locus heterogeneity.
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Affiliation(s)
- Bashayer R Al-Mubarak
- Behavioral Genetics unit, Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia.
- Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia.
| | - Aisha Omar
- Behavioral Genetics unit, Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia
| | - Batoul Baz
- Behavioral Genetics unit, Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia
- Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Basma Al-Abdulaziz
- Behavioral Genetics unit, Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia
- National center for genomics technology, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Amna I Magrashi
- Behavioral Genetics unit, Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia
| | - Eman Al-Yemni
- Behavioral Genetics unit, Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia
- Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Amjad Jabaan
- Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Dorota Monies
- Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
- Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia
| | - Mohamed Abouelhoda
- Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
- Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia
- Systems and Biomedical Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt
| | - Dejene Abebe
- Psychiatry Department, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia
| | | | - Nada A Al-Tassan
- Behavioral Genetics unit, Department of Genetics, King Faisal Specialist Hospital and Research Center, P.O Box 3354, Riyadh, 11211, Saudi Arabia.
- Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia.
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12
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Autophagy-dependent filopodial kinetics restrict synaptic partner choice during Drosophila brain wiring. Nat Commun 2020; 11:1325. [PMID: 32165611 PMCID: PMC7067798 DOI: 10.1038/s41467-020-14781-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/31/2020] [Indexed: 12/26/2022] Open
Abstract
Brain wiring is remarkably precise, yet most neurons readily form synapses with incorrect partners when given the opportunity. Dynamic axon-dendritic positioning can restrict synaptogenic encounters, but the spatiotemporal interaction kinetics and their regulation remain essentially unknown inside developing brains. Here we show that the kinetics of axonal filopodia restrict synapse formation and partner choice for neurons that are not otherwise prevented from making incorrect synapses. Using 4D imaging in developing Drosophila brains, we show that filopodial kinetics are regulated by autophagy, a prevalent degradation mechanism whose role in brain development remains poorly understood. With surprising specificity, autophagosomes form in synaptogenic filopodia, followed by filopodial collapse. Altered autophagic degradation of synaptic building material quantitatively regulates synapse formation as shown by computational modeling and genetic experiments. Increased filopodial stability enables incorrect synaptic partnerships. Hence, filopodial autophagy restricts inappropriate partner choice through a process of kinetic exclusion that critically contributes to wiring specificity.
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13
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Linneweber GA, Andriatsilavo M, Dutta SB, Bengochea M, Hellbruegge L, Liu G, Ejsmont RK, Straw AD, Wernet M, Hiesinger PR, Hassan BA. A neurodevelopmental origin of behavioral individuality in the Drosophila visual system. Science 2020; 367:1112-1119. [DOI: 10.1126/science.aaw7182] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 09/26/2019] [Accepted: 01/27/2020] [Indexed: 01/10/2023]
Abstract
The genome versus experience dichotomy has dominated understanding of behavioral individuality. By contrast, the role of nonheritable noise during brain development in behavioral variation is understudied. Using Drosophila melanogaster, we demonstrate a link between stochastic variation in brain wiring and behavioral individuality. A visual system circuit called the dorsal cluster neurons (DCN) shows nonheritable, interindividual variation in right/left wiring asymmetry and controls object orientation in freely walking flies. We show that DCN wiring asymmetry instructs an individual’s object responses: The greater the asymmetry, the better the individual orients toward a visual object. Silencing DCNs abolishes correlations between anatomy and behavior, whereas inducing DCN asymmetry suffices to improve object responses.
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14
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Mao Y, Fisher DW, Yang S, Keszycki RM, Dong H. Protein-protein interactions underlying the behavioral and psychological symptoms of dementia (BPSD) and Alzheimer's disease. PLoS One 2020; 15:e0226021. [PMID: 31951614 PMCID: PMC6968845 DOI: 10.1371/journal.pone.0226021] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 11/19/2019] [Indexed: 12/25/2022] Open
Abstract
Alzheimer’s Disease (AD) is a devastating neurodegenerative disorder currently affecting 45 million people worldwide, ranking as the 6th highest cause of death. Throughout the development and progression of AD, over 90% of patients display behavioral and psychological symptoms of dementia (BPSD), with some of these symptoms occurring before memory deficits and therefore serving as potential early predictors of AD-related cognitive decline. However, the biochemical links between AD and BPSD are not known. In this study, we explored the molecular interactions between AD and BPSD using protein-protein interaction (PPI) networks built from OMIM (Online Mendelian Inheritance in Man) genes that were related to AD and two distinct BPSD domains, the Affective Domain and the Hyperactivity, Impulsivity, Disinhibition, and Aggression (HIDA) Domain. Our results yielded 8 unique proteins for the Affective Domain (RHOA, GRB2, PIK3R1, HSPA4, HSP90AA1, GSK3beta, PRKCZ, and FYN), 5 unique proteins for the HIDA Domain (LRP1, EGFR, YWHAB, SUMO1, and EGR1), and 6 shared proteins between both BPSD domains (APP, UBC, ELAV1, YWHAZ, YWHAE, and SRC) and AD. These proteins might suggest specific targets and pathways that are involved in the pathogenesis of these BPSD domains in AD.
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Affiliation(s)
- Yimin Mao
- School of Information and Technology, Jiangxi University of Science and Technology, Jiangxi, China
- Applied Science Institute, Jiangxi University of Science and Technology, Jiangxi, China
| | - Daniel W. Fisher
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Shuxing Yang
- School of Information and Technology, Jiangxi University of Science and Technology, Jiangxi, China
| | - Rachel M. Keszycki
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Hongxin Dong
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
- * E-mail:
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15
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Luck R, Urban S, Karakatsani A, Harde E, Sambandan S, Nicholson L, Haverkamp S, Mann R, Martin-Villalba A, Schuman EM, Acker-Palmer A, Ruiz de Almodóvar C. VEGF/VEGFR2 signaling regulates hippocampal axon branching during development. eLife 2019; 8:49818. [PMID: 31868583 PMCID: PMC6927742 DOI: 10.7554/elife.49818] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 11/14/2019] [Indexed: 12/20/2022] Open
Abstract
Axon branching is crucial for proper formation of neuronal networks. Although originally identified as an angiogenic factor, VEGF also signals directly to neurons to regulate their development and function. Here we show that VEGF and its receptor VEGFR2 (also known as KDR or FLK1) are expressed in mouse hippocampal neurons during development, with VEGFR2 locally expressed in the CA3 region. Activation of VEGF/VEGFR2 signaling in isolated hippocampal neurons results in increased axon branching. Remarkably, inactivation of VEGFR2 also results in increased axon branching in vitro and in vivo. The increased CA3 axon branching is not productive as these axons are less mature and form less functional synapses with CA1 neurons. Mechanistically, while VEGF promotes the growth of formed branches without affecting filopodia formation, loss of VEGFR2 increases the number of filopodia and enhances the growth rate of new branches. Thus, a controlled VEGF/VEGFR2 signaling is required for proper CA3 hippocampal axon branching during mouse hippocampus development.
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Affiliation(s)
- Robert Luck
- Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany.,European Center for Angioscience, Medicine Faculty Mannheim, Heidelberg University, Heidelberg, Germany.,Institute for Transfusion Medicine and Immunology, Medicine Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Severino Urban
- Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany
| | - Andromachi Karakatsani
- Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany.,European Center for Angioscience, Medicine Faculty Mannheim, Heidelberg University, Heidelberg, Germany.,Institute for Transfusion Medicine and Immunology, Medicine Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Eva Harde
- Institute of Cell Biology and Neuroscience, University of Frankfurt, Frankfurt am Main, Germany.,Neurovascular Interface group, Max Planck Institute for Brain Research, Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Frankfurt am Main, Germany
| | - Sivakumar Sambandan
- Department of Synaptic Plasticity, Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - LaShae Nicholson
- Institute of Cell Biology and Neuroscience, University of Frankfurt, Frankfurt am Main, Germany.,Neurovascular Interface group, Max Planck Institute for Brain Research, Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Frankfurt am Main, Germany
| | - Silke Haverkamp
- Imaging Facility, Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Rebecca Mann
- Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany
| | - Ana Martin-Villalba
- Department of Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Erin Margaret Schuman
- Department of Synaptic Plasticity, Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Amparo Acker-Palmer
- Institute of Cell Biology and Neuroscience, University of Frankfurt, Frankfurt am Main, Germany.,Neurovascular Interface group, Max Planck Institute for Brain Research, Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Frankfurt am Main, Germany
| | - Carmen Ruiz de Almodóvar
- Biochemistry Center (BZH), University of Heidelberg, Heidelberg, Germany.,European Center for Angioscience, Medicine Faculty Mannheim, Heidelberg University, Heidelberg, Germany.,Institute for Transfusion Medicine and Immunology, Medicine Faculty Mannheim, Heidelberg University, Heidelberg, Germany
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16
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Qu Y, Hahn I, Lees M, Parkin J, Voelzmann A, Dorey K, Rathbone A, Friel CT, Allan VJ, Okenve-Ramos P, Sanchez-Soriano N, Prokop A. Efa6 protects axons and regulates their growth and branching by inhibiting microtubule polymerisation at the cortex. eLife 2019; 8:e50319. [PMID: 31718774 PMCID: PMC6884004 DOI: 10.7554/elife.50319] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/06/2019] [Indexed: 12/12/2022] Open
Abstract
Cortical collapse factors affect microtubule (MT) dynamics at the plasma membrane. They play important roles in neurons, as suggested by inhibition of axon growth and regeneration through the ARF activator Efa6 in C. elegans, and by neurodevelopmental disorders linked to the mammalian kinesin Kif21A. How cortical collapse factors influence axon growth is little understood. Here we studied them, focussing on the function of Drosophila Efa6 in experimentally and genetically amenable fly neurons. First, we show that Drosophila Efa6 can inhibit MTs directly without interacting molecules via an N-terminal 18 amino acid motif (MT elimination domain/MTED) that binds tubulin and inhibits microtubule growth in vitro and cells. If N-terminal MTED-containing fragments are in the cytoplasm they abolish entire microtubule networks of mouse fibroblasts and whole axons of fly neurons. Full-length Efa6 is membrane-attached, hence primarily blocks MTs in the periphery of fibroblasts, and explorative MTs that have left axonal bundles in neurons. Accordingly, loss of Efa6 causes an increase of explorative MTs: in growth cones they enhance axon growth, in axon shafts they cause excessive branching, as well as atrophy through perturbations of MT bundles. Efa6 over-expression causes the opposite phenotypes. Taken together, our work conceptually links molecular and sub-cellular functions of cortical collapse factors to axon growth regulation and reveals new roles in axon branching and in the prevention of axonal atrophy. Furthermore, the MTED delivers a promising tool that can be used to inhibit MTs in a compartmentalised fashion when fusing it to specifically localising protein domains.
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Affiliation(s)
- Yue Qu
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Ines Hahn
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Meredith Lees
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Jill Parkin
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - André Voelzmann
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Karel Dorey
- Faculty of Biology, Medicine and Health, School of Medical SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Alex Rathbone
- School of Life Sciences, Faculty of Medicine and Health SciencesThe University of NottinghamNottinghamUnited Kingdom
| | - Claire T Friel
- School of Life Sciences, Faculty of Medicine and Health SciencesThe University of NottinghamNottinghamUnited Kingdom
| | - Victoria J Allan
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Pilar Okenve-Ramos
- Department of Cellular and Molecular Physiology,Institute of Translational MedicineUniversity of LiverpoolLiverpoolUnited Kingdom
| | - Natalia Sanchez-Soriano
- Department of Cellular and Molecular Physiology,Institute of Translational MedicineUniversity of LiverpoolLiverpoolUnited Kingdom
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
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17
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Hiesinger PR, Hassan BA. The Evolution of Variability and Robustness in Neural Development. Trends Neurosci 2018; 41:577-586. [DOI: 10.1016/j.tins.2018.05.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/10/2018] [Accepted: 05/15/2018] [Indexed: 11/26/2022]
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18
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Sabado V, Nagoshi E. Single-cell Resolution Fluorescence Live Imaging of Drosophila Circadian Clocks in Larval Brain Culture. J Vis Exp 2018. [PMID: 29443100 DOI: 10.3791/57015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The circadian pacemaker circuit orchestrates rhythmic behavioral and physiological outputs coordinated with environmental cues, such as day/night cycles. The molecular clock within each pacemaker neuron generates circadian rhythms in gene expression, which underlie the rhythmic neuronal functions essential to the operation of the circuit. Investigation of the properties of the individual molecular oscillators in different subclasses of pacemaker neurons and their interaction with neuronal signaling yields a better understanding of the circadian pacemaker circuit. Here, we present a time-lapse fluorescent microscopy approach developed to monitor the molecular clockwork in clock neurons of cultured Drosophila larval brain. This method allows the multi-day recording of the rhythms of genetically encoded fluorescent circadian reporters at single-cell resolution. This setup can be combined with pharmacological manipulations to closely analyze real-time response of the molecular clock to various compounds. Beyond circadian rhythms, this multipurpose method in combination with powerful Drosophila genetic techniques offers the possibility to study diverse neuronal or molecular processes in live brain tissue.
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Affiliation(s)
| | - Emi Nagoshi
- Department of Genetics and Evolution, University of Geneva;
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19
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Regulation of Drosophila Brain Wiring by Neuropil Interactions via a Slit-Robo-RPTP Signaling Complex. Dev Cell 2017; 39:267-278. [PMID: 27780041 PMCID: PMC5084709 DOI: 10.1016/j.devcel.2016.09.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 03/29/2016] [Accepted: 08/25/2016] [Indexed: 11/05/2022]
Abstract
The axonal wiring molecule Slit and its Round-About (Robo) receptors are conserved regulators of nerve cord patterning. Robo receptors also contribute to wiring brain circuits. Whether molecular mechanisms regulating these signals are modified to fit more complex brain wiring processes is unclear. We investigated the role of Slit and Robo receptors in wiring Drosophila higher-order brain circuits and identified differences in the cellular and molecular mechanisms of Robo/Slit function. First, we find that signaling by Robo receptors in the brain is regulated by the Receptor Protein Tyrosine Phosphatase RPTP69d. RPTP69d increases membrane availability of Robo3 without affecting its phosphorylation state. Second, we detect no midline localization of Slit during brain development. Instead, Slit is enriched in the mushroom body, a neuronal structure covering large areas of the brain. Thus, a divergent molecular mechanism regulates neuronal circuit wiring in the Drosophila brain, partly in response to signals from the mushroom body. In the Drosophila brain, mushroom bodies are a source of the Slit guidance cue Slit regulates axon growth in the vicinity of mushroom bodies via Robo receptors The phosphatase RPTP69D regulates Robo signaling in the brain RPTP69D regulates Robo3 membrane presentation independent of its enzymatic activity
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20
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Copenhaver PF, Ramaker JM. Neuronal migration during development and the amyloid precursor protein. CURRENT OPINION IN INSECT SCIENCE 2016; 18:1-10. [PMID: 27939704 PMCID: PMC5157842 DOI: 10.1016/j.cois.2016.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 08/06/2016] [Indexed: 06/06/2023]
Abstract
The Amyloid Precursor Protein (APP) is the source of amyloid peptides that accumulate in Alzheimer's disease. However, members of the APP family are strongly expressed in the developing nervous systems of invertebrates and vertebrates, where they regulate neuronal guidance, synaptic remodeling, and injury responses. In contrast to mammals, insects express only one APP ortholog (APPL), simplifying investigations into its normal functions. Recent studies have shown that APPL regulates neuronal migration in the developing insect nervous system, analogous to the roles ascribed to APP family proteins in the mammalian cortex. The comparative simplicity of insect systems offers new opportunities for deciphering the signaling mechanisms by which this enigmatic class of proteins contributes to the formation and function of the nervous system.
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Affiliation(s)
- Philip F Copenhaver
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Jenna M Ramaker
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR 97239, USA; Department of Pathology, Oregon Health & Science University, Portland, OR 97239, USA
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21
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Oliva C, Hassan BA. Receptor Tyrosine Kinases and Phosphatases in Neuronal Wiring: Insights From Drosophila. Curr Top Dev Biol 2016; 123:399-432. [PMID: 28236973 DOI: 10.1016/bs.ctdb.2016.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Tyrosine phosphorylation is at the crossroads of many signaling pathways. Brain wiring is not an exception, and several receptor tyrosine kinases (RTKs) and tyrosine receptor phosphates (RPTPs) have been involved in this process. Considerable work has been done on RTKs, and for many of them, detailed molecular mechanisms and functions in several systems have been characterized. In contrast, RPTPs have been studied considerably less and little is known about their ligands and substrates. In both families, we find redundancy between different members to accomplish particular wiring patterns. Strikingly, some RTKs and RPTPs have lost their catalytic activity during evolution, but not their importance in biological processes. In this regard, we have to keep in mind that these proteins have multiple domains and some of their functions are independent of tyrosine phosphorylation/dephosphorylation. Since RTKs and RPTPs are enzymes involved not only in early stages of axon and dendrite pathfinding but also in synapse formation and physiology, they have a potential as drug targets. Drosophila has been a key model organism in the search of a better understanding of brain wiring, and its sophisticated toolbox is very suitable for studying the function of genes with pleiotropic functions such as RTKs and RPTPs, from wiring to synaptic formation and function. In these review, we mainly cover findings from this model organism and complement them with discoveries in vertebrate systems.
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Affiliation(s)
- Carlos Oliva
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad of Chile, Santiago, Chile.
| | - Bassem A Hassan
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, AP-HP, Institut du Cerveau et la Moelle (ICM)-Hôpital Pitié-Salpêtrière, Boulevard de l'Hôpital, Paris, France.
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22
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Voelzmann A, Okenve-Ramos P, Qu Y, Chojnowska-Monga M, del Caño-Espinel M, Prokop A, Sanchez-Soriano N. Tau and spectraplakins promote synapse formation and maintenance through Jun kinase and neuronal trafficking. eLife 2016; 5:e14694. [PMID: 27501441 PMCID: PMC4977155 DOI: 10.7554/elife.14694] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 07/12/2016] [Indexed: 11/13/2022] Open
Abstract
The mechanisms regulating synapse numbers during development and ageing are essential for normal brain function and closely linked to brain disorders including dementias. Using Drosophila, we demonstrate roles of the microtubule-associated protein Tau in regulating synapse numbers, thus unravelling an important cellular requirement of normal Tau. In this context, we find that Tau displays a strong functional overlap with microtubule-binding spectraplakins, establishing new links between two different neurodegenerative factors. Tau and the spectraplakin Short Stop act upstream of a three-step regulatory cascade ensuring adequate delivery of synaptic proteins. This cascade involves microtubule stability as the initial trigger, JNK signalling as the central mediator, and kinesin-3 mediated axonal transport as the key effector. This cascade acts during development (synapse formation) and ageing (synapse maintenance) alike. Therefore, our findings suggest novel explanations for intellectual disability in Tau deficient individuals, as well as early synapse loss in dementias including Alzheimer's disease.
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Affiliation(s)
- Andre Voelzmann
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - Pilar Okenve-Ramos
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Yue Qu
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - Monika Chojnowska-Monga
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Manuela del Caño-Espinel
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Andreas Prokop
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - Natalia Sanchez-Soriano
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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23
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Mario LC, Borghesi J, Crivellari-Damasceno WT, Favaron PO, Carreira ACO, Will SEAL, Maria DA, Miglino MA. Egg and fourth instar larvae gut of Aedes aegypti as a source of stem cells. Tissue Cell 2016; 48:558-65. [PMID: 27401144 DOI: 10.1016/j.tice.2016.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/20/2016] [Accepted: 05/14/2016] [Indexed: 11/17/2022]
Abstract
According to the World Health Organization, 2015 registered more than 1.206.172 cases of Dengue in the Americas. Recently, the Aedes aegypti has been not only related to Dengue, but also with cases of Zika virus and Chikungunya. Due to its epidemiological importance, this study characterized the morphology of the embryonated eggs of A. aegypti and provided a protocol to culture stem cells from eggs and digestive tract of fourth instar larvae in order to examine cell biology and expression of markers in these vectors. Cells were isolated and cultured in DMEM-High at 28°C, and their morphology, cell cycle and immunophenotyping were examined. Morphologically, embryos were at the end of the embryonic period and showed: head, thorax, and abdomen with eight abdominal segments. The embryonic tissues expressed markers related to cell proliferation (PCNA), pluripotency (Sox2 and OCT3/4), neural cells (Nestin), mesenchymal cells (Vimentin and Stro-1), and endosomal cells (GM130 and RAB5). In culture, cells from both tissues (eggs and larvae gut) were composed by a heterogeneous population. The cells had a globoid shape and small size. Cell cycle analysis on passage 1 (P1) showed 27.5%±2.0% of cell debris, 68% of cells on G0-G1 phase, 30.2% on S phase, 1.9%±0.5% on G2-M phase. In addition, cells on passage 2 showed: 10% of cell debris, 92.4% of cells on G0-G1 phase, 6.8% on S phase, 0.6% on G2-M phase. Embryonated eggs expressed markers involved with pluripotency (Sox2 and Oct 3/4), mesenchymal cells (vimentin and Stro-1), neural cells (Nestin), and cellular death by apoptosis (Caspase 3). Specific endosomal markers for insect cells (GM130 and RAB5) were also highly expressed. In cell culture of A. aegypti larvae gut the same labeling pattern was observed, with a small decrease in the expression of mesenchymal (vimentin and Stro-1) and neural (Nestin) markers. In summary, we were able to establish a protocol to culture embryonated eggs and larvae gut of A. aegypti, describing the characteristics of undifferentiated cells, as well as the cell cycle and expression of markers, which can be used for biotechnology studies for the biological control of this vector.
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Affiliation(s)
- Lara C Mario
- Departament of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil.
| | - Jéssica Borghesi
- Departament of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Wilson T Crivellari-Damasceno
- Departament of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil; Laboratory of Biochemistry and Biophysics, Butantan Institute, Sao Paulo, SP, Brazil
| | - Phelipe O Favaron
- Departament of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Ana Claudia O Carreira
- Center for Molecular and Cellular Therapy (NUCEL) and Center for Cellular and Molecular Therapy (NETCEM), School of Medicine, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Sonia E A L Will
- Laboratory of Biochemistry and Biophysics, Butantan Institute, Sao Paulo, SP, Brazil
| | - Durvanei A Maria
- Departament of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil; Laboratory of Biochemistry and Biophysics, Butantan Institute, Sao Paulo, SP, Brazil
| | - Maria A Miglino
- Departament of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, SP, Brazil
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24
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Hassan BA, Hiesinger PR. Beyond Molecular Codes: Simple Rules to Wire Complex Brains. Cell 2016; 163:285-91. [PMID: 26451480 DOI: 10.1016/j.cell.2015.09.031] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Indexed: 11/30/2022]
Abstract
Molecular codes, like postal zip codes, are generally considered a robust way to ensure the specificity of neuronal target selection. However, a code capable of unambiguously generating complex neural circuits is difficult to conceive. Here, we re-examine the notion of molecular codes in the light of developmental algorithms. We explore how molecules and mechanisms that have been considered part of a code may alternatively implement simple pattern formation rules sufficient to ensure wiring specificity in neural circuits. This analysis delineates a pattern-based framework for circuit construction that may contribute to our understanding of brain wiring.
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Affiliation(s)
- Bassem A Hassan
- Center for the Biology of Disease, VIB, 3000 Leuven, Belgium; Center for Human Genetics, University of Leuven School of Medicine, 3000 Leuven, Belgium.
| | - P Robin Hiesinger
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charite Universitätsmedizin Berlin, 10117 Berlin, Germany.
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25
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Özel MN, Langen M, Hassan BA, Hiesinger PR. Filopodial dynamics and growth cone stabilization in Drosophila visual circuit development. eLife 2015; 4. [PMID: 26512889 PMCID: PMC4728134 DOI: 10.7554/elife.10721] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/26/2015] [Indexed: 01/04/2023] Open
Abstract
Filopodial dynamics are thought to control growth cone guidance, but the types and roles of growth cone dynamics underlying neural circuit assembly in a living brain are largely unknown. To address this issue, we have developed long-term, continuous, fast and high-resolution imaging of growth cone dynamics from axon growth to synapse formation in cultured Drosophila brains. Using R7 photoreceptor neurons as a model we show that >90% of the growth cone filopodia exhibit fast, stochastic dynamics that persist despite ongoing stepwise layer formation. Correspondingly, R7 growth cones stabilize early and change their final position by passive dislocation. N-Cadherin controls both fast filopodial dynamics and growth cone stabilization. Surprisingly, loss of N-Cadherin causes no primary targeting defects, but destabilizes R7 growth cones to jump between correct and incorrect layers. Hence, growth cone dynamics can influence wiring specificity without a direct role in target recognition and implement simple rules during circuit assembly. DOI:http://dx.doi.org/10.7554/eLife.10721.001 Genes encode complicated developmental processes, but it is clear that genetic information cannot encode each and every individual connection that forms between the nerve cells in a brain. Instead, the individual cells and nerve endings must make decisions during brain development. Up until now, few examples were known for how these nerve endings move and choose their paths and partners in a living, developing brain. The fruit fly Drosophila provides a useful model to explore the ‘wiring’ of nerve cells in the brain, partly because a fruit fly’s brain develops within a few days. However, most previous studies have relied on identifying mutant flies with disrupted brain wiring and studying them using still images. Now, Özel et al. have developed a new imaging method that has enough resolution and speed over sufficiently long periods to track the growing nerve endings in a developing fly brain. The method was applied to a model nerve cell in the fly’s visual system. This revealed that most of this nerve’s dynamic changes are short-lived and random, and appear to help to stabilize the developing nerve ending, rather than guide it to a target. Özel et al. also found that a protein called N-Cadherin, previously thought to be required for the targeting of developing nerve endings, actually plays a role in their stabilization. These findings uncover the roles of changes in nerve endings during long-term brain development; this was previously largely unknown for any organism. The next stage in this research will involve further analyses of both wild type and mutant flies to try and work out general principles about how the brain develops via the decoding of genetic information. DOI:http://dx.doi.org/10.7554/eLife.10721.002
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Affiliation(s)
- Mehmet Neset Özel
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States.,Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charite Universitätsmedizin Berlin, Berlin, Germany
| | - Marion Langen
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Bassem A Hassan
- Center for the Biology of Disease, Vlaams Instituut voor Biotechnologie, Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, Leuven, Belgium
| | - P Robin Hiesinger
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States.,Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charite Universitätsmedizin Berlin, Berlin, Germany
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Rabinovich D, Mayseless O, Schuldiner O. Long term ex vivo culturing of Drosophila brain as a method to live image pupal brains: insights into the cellular mechanisms of neuronal remodeling. Front Cell Neurosci 2015; 9:327. [PMID: 26379498 PMCID: PMC4547045 DOI: 10.3389/fncel.2015.00327] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/07/2015] [Indexed: 01/01/2023] Open
Abstract
Holometabolous insects, including Drosophila melanogaster, undergo complete metamorphosis that includes a pupal stage. During metamorphosis, the Drosophila nervous system undergoes massive remodeling and growth, that include cell death and large-scale axon and synapse elimination as well as neurogenesis, developmental axon regrowth, and formation of new connections. Neuronal remodeling is an essential step in the development of vertebrate and invertebrate nervous systems. Research on the stereotypic remodeling of Drosophila mushroom body (MB) γ neurons has contributed to our knowledge of the molecular mechanisms of remodeling but our knowledge of the cellular mechanisms remain poorly understood. A major hurdle in understanding various dynamic processes that occur during metamorphosis is the lack of time-lapse resolution. The pupal case and opaque fat bodies that enwrap the central nervous system (CNS) make live-imaging of the central brain in-vivo impossible. We have established an ex vivo long-term brain culture system that supports the development and neuronal remodeling of pupal brains. By optimizing culture conditions and dissection protocols, we have observed development in culture at kinetics similar to what occurs in vivo. Using this new method, we have obtained the first time-lapse sequence of MB γ neurons undergoing remodeling in up to a single cell resolution. We found that axon pruning is initiated by blebbing, followed by one-two nicks that seem to initiate a more widely spread axon fragmentation. As such, we have set up some of the tools and methodologies needed for further exploration of the cellular mechanisms of neuronal remodeling, not limited to the MB. The long-term ex vivo brain culture system that we report here could be used to study dynamic aspects of neurodevelopment of any Drosophila neuron.
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Affiliation(s)
- Dana Rabinovich
- Department of Molecular Cell Biology, Weizmann Institute of Sciences Rehovot, Israel
| | - Oded Mayseless
- Department of Molecular Cell Biology, Weizmann Institute of Sciences Rehovot, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences Rehovot, Israel
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