1
|
Ghosh G, Das D, Nandi A, De S, Gangappa SN, Prasad M. Ecdysone regulates phagocytic cell fate of epithelial cells in developing Drosophila eggs. J Cell Biol 2025; 224:e202411073. [PMID: 40434296 PMCID: PMC12118371 DOI: 10.1083/jcb.202411073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2024] [Revised: 04/01/2025] [Accepted: 05/12/2025] [Indexed: 05/29/2025] Open
Abstract
Acquisition of nonprofessional phagocytic cell fate plays an important role in sculpting functional metazoan organs and maintaining overall tissue homeostasis. Though physiologically highly relevant, how the normal epithelial cells acquire phagocytic fate is still mostly unclear. We have employed the Drosophila ovary model to demonstrate that the classical ecdysone signaling in the somatic epithelial follicle cells (AFCs) aids the removal of germline nurse cells (NCs) in late oogenesis. Our live-cell imaging data reveal a novel phenomenon wherein collective behavior of 4-5 AFCs is required for clearing a single NC. By employing classical genetics, molecular biology, and yeast one-hybrid assay, we demonstrate that ecdysone modulates the phagocytic disposition of AFCs at two levels. It regulates the epithelial-mesenchymal transition of the AFCs through Serpent and modulates the phagocytic behavior of the AFCs through Croquemort and Draper. Our data provide unprecedented novel molecular insights into how ecdysone signaling reprograms AFCs toward a phagocytic fate.
Collapse
Affiliation(s)
- Gaurab Ghosh
- Department of Biological Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur, India
| | - Devyan Das
- Department of Biological Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur, India
| | - Abhrajyoti Nandi
- Department of Biological Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur, India
| | - Souvik De
- Department of Biological Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur, India
| | - Sreeramaiah N. Gangappa
- Department of Biological Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur, India
| | - Mohit Prasad
- Department of Biological Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur, India
| |
Collapse
|
2
|
Alassaf M, Madan A, Ranganathan S, Marschall S, Wong JJ, Goldberg ZH, Brent AE, Rajan A. Adipocyte metabolic state regulates glial phagocytic function. Cell Rep 2025; 44:115704. [PMID: 40372917 DOI: 10.1016/j.celrep.2025.115704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2024] [Revised: 03/17/2025] [Accepted: 04/25/2025] [Indexed: 05/17/2025] Open
Abstract
Excess dietary sugar profoundly impacts organismal metabolism and health, yet it remains unclear how metabolic adaptations in adipose tissue influence other organs, including the brain. Here, we show that a high-sugar diet (HSD) in Drosophila reduces adipocyte glycolysis and mitochondrial pyruvate uptake, shifting metabolism toward fatty acid oxidation and ketogenesis. These metabolic changes trigger mitochondrial oxidation and elevate antioxidant responses. Adipocyte-specific manipulations of glycolysis, lipid metabolism, or mitochondrial dynamics non-autonomously modulate Draper expression in brain ensheathing glia, key cells responsible for neuronal debris clearance. Adipocyte-derived ApoB-containing lipoproteins maintain basal Draper levels in glia via LpR1, critical for effective glial phagocytic activity. Accordingly, reducing ApoB or LpR1 impairs glial clearance of degenerating neuronal debris after injury. Collectively, our findings demonstrate that dietary sugar-induced shifts in adipocyte metabolism substantially influence brain health by modulating glial phagocytosis, identifying adipocyte-derived ApoB lipoproteins as essential systemic mediators linking metabolic state with neuroprotective functions.
Collapse
Affiliation(s)
- Mroj Alassaf
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Aditi Madan
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Sunidhi Ranganathan
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Shannon Marschall
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Jordan J Wong
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Zachary H Goldberg
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Ava E Brent
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Akhila Rajan
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA.
| |
Collapse
|
3
|
Adell T, Cebrià F, Abril JF, Araújo SJ, Corominas M, Morey M, Serras F, González-Estévez C. Cell death in regeneration and cell turnover: Lessons from planarians and Drosophila. Semin Cell Dev Biol 2025; 169:103605. [PMID: 40139139 DOI: 10.1016/j.semcdb.2025.103605] [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: 11/29/2024] [Revised: 02/27/2025] [Accepted: 03/09/2025] [Indexed: 03/29/2025]
Abstract
Programmed cell death plays a crucial role during tissue turnover in all animal species, and it is also essential during regeneration, serving as a key signalling mechanism to promote tissue repair and regrowth. In freshwater planarians, remarkable regenerative abilities are supported by neoblasts, a population of adult stem cells, which enable high somatic cell turnover. Cell death in planarians occurs continuously during regeneration and adult homeostasis, underscoring its critical role in tissue remodeling and repair. However, the exact mechanisms regulating cell death in these organisms remain elusive. In contrast, Drosophila melanogaster serves as a powerful model for studying programmed cell death in development, metamorphosis, and adult tissue maintenance, leveraging advanced genetic tools and visualization techniques. In Drosophila, cell death sculpts tissues, eliminates larval structures during metamorphosis, and supports homeostasis in adulthood. Despite limited regenerative capacity compared to planarians, Drosophila provides unique insights into cell death's regulatory mechanisms. Comparative analysis of these two systems highlights both conserved and divergent roles of programmed cell death in tissue renewal and regeneration. This review synthesizes the latest knowledge of programmed cell death in planarians and Drosophila, aiming to illuminate shared principles and system-specific adaptations, with relevance to tissue repair across biological systems.
Collapse
Affiliation(s)
- Teresa Adell
- Department of Genetics, Microbiology and Statistics, School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Av. Diagonal 643, Edifici Prevosti 1st floor, Barcelona 08028, Spain.
| | - Francesc Cebrià
- Department of Genetics, Microbiology and Statistics, School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Av. Diagonal 643, Edifici Prevosti 1st floor, Barcelona 08028, Spain
| | - Josep F Abril
- Department of Genetics, Microbiology and Statistics, School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Av. Diagonal 643, Edifici Prevosti 1st floor, Barcelona 08028, Spain
| | - Sofia J Araújo
- Department of Genetics, Microbiology and Statistics, School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Av. Diagonal 643, Edifici Prevosti 1st floor, Barcelona 08028, Spain
| | - Montserrat Corominas
- Department of Genetics, Microbiology and Statistics, School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Av. Diagonal 643, Edifici Prevosti 1st floor, Barcelona 08028, Spain
| | - Marta Morey
- Department of Genetics, Microbiology and Statistics, School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Av. Diagonal 643, Edifici Prevosti 1st floor, Barcelona 08028, Spain
| | - Florenci Serras
- Department of Genetics, Microbiology and Statistics, School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Av. Diagonal 643, Edifici Prevosti 1st floor, Barcelona 08028, Spain
| | - Cristina González-Estévez
- Department of Genetics, Microbiology and Statistics, School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Av. Diagonal 643, Edifici Prevosti 1st floor, Barcelona 08028, Spain.
| |
Collapse
|
4
|
Nelson N, Miller V, Broadie K. Neuron-to-glia and glia-to-glia signaling directs critical period experience-dependent synapse pruning. Front Cell Dev Biol 2025; 13:1540052. [PMID: 40040788 PMCID: PMC11876149 DOI: 10.3389/fcell.2025.1540052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2024] [Accepted: 01/31/2025] [Indexed: 03/06/2025] Open
Abstract
Experience-dependent glial synapse pruning plays a pivotal role in sculpting brain circuit connectivity during early-life critical periods of development. Recent advances suggest a layered cascade of intercellular communication between neurons and glial phagocytes orchestrates this precise, targeted synapse elimination. We focus here on studies from the powerful Drosophila forward genetic model, with reference to complementary findings from mouse work. We present both neuron-to-glia and glia-to-glia intercellular signaling pathways directing experience-dependent glial synapse pruning. We discuss a putative hierarchy of secreted long-distance cues and cell surface short-distance cues that act to sequentially orchestrate glia activation, infiltration, target recognition, engulfment, and then phagocytosis for synapse pruning. Ligand-receptor partners mediating these stages in different contexts are discussed from recent Drosophila and mouse studies. Signaling cues include phospholipids, small neurotransmitters, insulin-like peptides, and proteins. Conserved receptors for these ligands are discussed, together with mechanisms where the receptor identity remains unknown. Potential mechanisms are proposed for the tight temporal-restriction of heightened experience-dependent glial synapse elimination during early-life critical periods, as well as potential means to re-open such plasticity at maturity.
Collapse
Affiliation(s)
- Nichalas Nelson
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, United States
| | - Vanessa Miller
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, United States
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, United States
- Department of Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, TN, United States
- Department of Pharmacology, Vanderbilt University and Medical Center, Nashville, TN, United States
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN, United States
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN, United States
| |
Collapse
|
5
|
Aviani MG, Menard F. Emerging Roles for MFG-E8 in Synapse Elimination. J Neurochem 2025; 169:e70009. [PMID: 39891478 DOI: 10.1111/jnc.70009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2024] [Revised: 01/15/2025] [Accepted: 01/17/2025] [Indexed: 02/03/2025]
Abstract
Synapse elimination is an essential process in the healthy nervous system and is dysregulated in many neuropathologies. Yet, the underlying molecular mechanisms and under what conditions they occur remain unclear. MFG-E8 is a secreted glycoprotein well known to act as an opsonin, tagging stressed and dying cells for engulfment by phagocytes. Opsonization of cells and debris by MFG-E8 for microglial phagocytosis in the CNS is well established, and its role in astrocytic phagocytosis, and trogocytosis-like engulfment of synapses is beginning to be explored. However, MFG-E8's function in other tissues is highly diverse, and evidence suggests that its role in the nervous system and on synapse elimination in particular may be more complex and varied than opsonization. In this review, we outline the documented direct and indirect effects of MFG-E8 on synapse elimination, while also proposing potential roles to be explored further, in particular, cytoskeletal reorganization of neurites and glia leading to synapse elimination by various mechanisms. Finally, we demonstrate the need for several open questions to be answered-chiefly, under what conditions might MFG-E8-mediated synapse elimination occur in favor of other mechanisms, and when might its activity be dysregulated, increasing unwanted synapse elimination and neurotoxicity?
Collapse
Affiliation(s)
- Marisa G Aviani
- Department of Biochemistry and Molecular Biology, I.K. Barber Faculty of Science, The University of British Columbia, Kelowna, British Columbia, Canada
| | - Fred Menard
- Department of Biochemistry and Molecular Biology, I.K. Barber Faculty of Science, The University of British Columbia, Kelowna, British Columbia, Canada
- Department of Chemistry, I.K. Barber Faculty of Science, The University of British Columbia, Kelowna, British Columbia, Canada
| |
Collapse
|
6
|
Leier HC, Foden AJ, Jindal DA, Wilkov AJ, Van der Linden Costello P, Vanderzalm PJ, Coutinho-Budd J, Tabuchi M, Broihier HT. Glia control experience-dependent plasticity in an olfactory critical period. eLife 2025; 13:RP100989. [PMID: 39883485 PMCID: PMC11781797 DOI: 10.7554/elife.100989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2025] Open
Abstract
Sensory experience during developmental critical periods has lifelong consequences for circuit function and behavior, but the molecular and cellular mechanisms through which experience causes these changes are not well understood. The Drosophila antennal lobe houses synapses between olfactory sensory neurons (OSNs) and downstream projection neurons (PNs) in stereotyped glomeruli. Many glomeruli exhibit structural plasticity in response to early-life odor exposure, indicating a general sensitivity of the fly olfactory circuitry to early sensory experience. We recently found that glia shape antennal lobe development in young adults, leading us to ask if glia also drive experience-dependent plasticity during this period. Here, we define a critical period for structural and functional plasticity of OSN-PN synapses in the ethyl butyrate (EB)-sensitive glomerulus VM7. EB exposure for the first 2 days post-eclosion drives large-scale reductions in glomerular volume, presynapse number, and post- synaptic activity. Crucially, pruning during the critical period has long-term consequences for circuit function since both OSN-PN synapse number and spontaneous activity of PNs remain persistently decreased following early-life odor exposure. The highly conserved engulfment receptor Draper is required for this critical period plasticity as ensheathing glia upregulate Draper, invade the VM7 glomerulus, and phagocytose OSN presynaptic terminals in response to critical-period EB exposure. Loss of Draper fully suppresses the morphological and physiological consequences of critical period odor exposure, arguing that phagocytic glia engulf intact synaptic terminals. These data demonstrate experience-dependent pruning of synapses and argue that Drosophila olfactory circuitry is a powerful model for defining the function of glia in critical period plasticity.
Collapse
Affiliation(s)
- Hans C Leier
- Department of Neurosciences, Case Western Reserve University School of MedicineClevelandUnited States
| | - Alexander J Foden
- Department of Neurosciences, Case Western Reserve University School of MedicineClevelandUnited States
| | - Darren A Jindal
- Department of Neurosciences, Case Western Reserve University School of MedicineClevelandUnited States
| | - Abigail J Wilkov
- Department of Neurosciences, Case Western Reserve University School of MedicineClevelandUnited States
| | | | - Pamela J Vanderzalm
- Department of Biology, John Carroll UniversityUniversity HeightsUnited States
| | - Jaeda Coutinho-Budd
- Department of Neuroscience, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Masashi Tabuchi
- Department of Neurosciences, Case Western Reserve University School of MedicineClevelandUnited States
| | - Heather T Broihier
- Department of Neurosciences, Case Western Reserve University School of MedicineClevelandUnited States
| |
Collapse
|
7
|
Hilu-Dadia R, Ghanem A, Vogelesang S, Ayoub M, Hakim-Mishnaevski K, Kurant E. Santa-maria is a glial phagocytic receptor that acts with SIMU to recognize and engulf apoptotic neurons. Cell Rep 2025; 44:115201. [PMID: 39799566 DOI: 10.1016/j.celrep.2024.115201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 12/08/2024] [Accepted: 12/20/2024] [Indexed: 01/15/2025] Open
Abstract
The elimination of superfluous neurons via apoptosis and subsequent glial phagocytosis is crucial for the development of the central nervous system (CNS). In Drosophila, two glial phagocytic receptors, six-microns-under (SIMU) and Draper, mediate the phagocytosis of apoptotic neurons during embryogenesis. However, in simu;draper double-mutant embryos, some apoptotic neurons are still engulfed by the glia, suggesting the involvement of additional receptors. Here, we discover the Drosophila CD36 homolog Santa-maria, a transmembrane receptor, which is specifically expressed in embryonic phagocytic glia and plays a major role in the recognition and engulfment steps of phagocytosis. Our data demonstrate that santa-maria genetically interacts with simu and draper, while the protein product binds apoptotic cells and physically interacts with the SIMU protein. Moreover, we reveal that triple knockout of genes for all three glial phagocytic receptors (i.e., simu, draper, and santa-maria) causes partial lethality, thus illuminating their role in development, particularly in the developing nervous system.
Collapse
Affiliation(s)
- Reut Hilu-Dadia
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 34988, Israel
| | - Aseel Ghanem
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 34988, Israel
| | - Shelly Vogelesang
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 34988, Israel
| | - Malak Ayoub
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 34988, Israel
| | - Ketty Hakim-Mishnaevski
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 34988, Israel
| | - Estee Kurant
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 34988, Israel.
| |
Collapse
|
8
|
Li T, Shi W, Ho MS, Zhang YQ. A Pvr-AP-1-Mmp1 signaling pathway is activated in astrocytes upon traumatic brain injury. eLife 2024; 12:RP87258. [PMID: 39480704 PMCID: PMC11527428 DOI: 10.7554/elife.87258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2024] Open
Abstract
Traumatic brain injury (TBI) caused by external mechanical forces is a major health burden worldwide, but the underlying mechanism in glia remains largely unclear. We report herein that Drosophila adults exhibit a defective blood-brain barrier, elevated innate immune responses, and astrocyte swelling upon consecutive strikes with a high-impact trauma device. RNA sequencing (RNA-seq) analysis of these astrocytes revealed upregulated expression of genes encoding PDGF and VEGF receptor-related (Pvr, a receptor tyrosine kinase), adaptor protein complex 1 (AP-1, a transcription factor complex of the c-Jun N-terminal kinase pathway) composed of Jun-related antigen (Jra) and kayak (kay), and matrix metalloproteinase 1 (Mmp1) following TBI. Interestingly, Pvr is both required and sufficient for AP-1 and Mmp1 upregulation, while knockdown of AP-1 expression in the background of Pvr overexpression in astrocytes rescued Mmp1 upregulation upon TBI, indicating that Pvr acts as the upstream receptor for the downstream AP-1-Mmp1 transduction. Moreover, dynamin-associated endocytosis was found to be an important regulatory step in downregulating Pvr signaling. Our results identify a new Pvr-AP-1-Mmp1 signaling pathway in astrocytes in response to TBI, providing potential targets for developing new therapeutic strategies for TBI.
Collapse
Affiliation(s)
- Tingting Li
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, University of Chinese Academy of Sciences, Chinese Academy of SciencesBeijingChina
| | - Wenwen Shi
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, University of Chinese Academy of Sciences, Chinese Academy of SciencesBeijingChina
| | - Margaret S Ho
- Institute of Neuroscience, National Yang Ming Chiao Tung UniversityTaipeiTaiwan
- Brain Research Center, National Yang Ming Chiao Tung UniversityTaipeiTaiwan
| | - Yong Q Zhang
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, University of Chinese Academy of Sciences, Chinese Academy of SciencesBeijingChina
| |
Collapse
|
9
|
Leier HC, Foden AJ, Jindal DA, Wilkov AJ, Costello PVDL, Vanderzalm PJ, Coutinho-Budd JC, Tabuchi M, Broihier HT. Glia control experience-dependent plasticity in an olfactory critical period. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.05.602232. [PMID: 39005309 PMCID: PMC11245089 DOI: 10.1101/2024.07.05.602232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Sensory experience during developmental critical periods has lifelong consequences for circuit function and behavior, but the molecular and cellular mechanisms through which experience causes these changes are not well understood. The Drosophila antennal lobe houses synapses between olfactory sensory neurons (OSNs) and downstream projection neurons (PNs) in stereotyped glomeruli. Many glomeruli exhibit structural plasticity in response to early-life odor exposure, indicating a general sensitivity of the fly olfactory circuitry to early sensory experience. We recently found that glia shape antennal lobe development in young adults, leading us to ask if glia also drive experience-dependent plasticity during this period. Here we define a critical period for structural and functional plasticity of OSN-PN synapses in the ethyl butyrate (EB)-sensitive glomerulus VM7. EB exposure for the first two days post-eclosion drives large-scale reductions in glomerular volume, presynapse number, and post-synaptic activity. Crucially, pruning during the critical period has long-term consequences for circuit function since both OSN-PN synapse number and spontaneous activity of PNs remain persistently decreased following early-life odor exposure. The highly conserved engulfment receptor Draper is required for this critical period plasticity as ensheathing glia upregulate Draper, invade the VM7 glomerulus, and phagocytose OSN presynaptic terminals in response to critical-period EB exposure. Loss of Draper fully suppresses the morphological and physiological consequences of critical period odor exposure, arguing that phagocytic glia engulf intact synaptic terminals. These data demonstrate experience-dependent pruning of synapses and argue that Drosophila olfactory circuitry is a powerful model for defining the function of glia in critical period plasticity.
Collapse
Affiliation(s)
- Hans C Leier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | - Alexander J Foden
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | - Darren A Jindal
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | - Abigail J Wilkov
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | | | - Pamela J Vanderzalm
- Department of Biology, John Carroll University, University Heights, United States
| | - Jaeda C Coutinho-Budd
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, United States
| | - Masashi Tabuchi
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| | - Heather T Broihier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States
| |
Collapse
|
10
|
Liu S, Alexander KD, Francis MM. Neural Circuit Remodeling: Mechanistic Insights from Invertebrates. J Dev Biol 2024; 12:27. [PMID: 39449319 PMCID: PMC11503349 DOI: 10.3390/jdb12040027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2024] [Revised: 10/07/2024] [Accepted: 10/10/2024] [Indexed: 10/26/2024] Open
Abstract
As nervous systems mature, neural circuit connections are reorganized to optimize the performance of specific functions in adults. This reorganization of connections is achieved through a remarkably conserved phase of developmental circuit remodeling that engages neuron-intrinsic and neuron-extrinsic molecular mechanisms to establish mature circuitry. Abnormalities in circuit remodeling and maturation are broadly linked with a variety of neurodevelopmental disorders, including autism spectrum disorders and schizophrenia. Here, we aim to provide an overview of recent advances in our understanding of the molecular processes that govern neural circuit remodeling and maturation. In particular, we focus on intriguing mechanistic insights gained from invertebrate systems, such as the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster. We discuss how transcriptional control mechanisms, synaptic activity, and glial engulfment shape specific aspects of circuit remodeling in worms and flies. Finally, we highlight mechanistic parallels across invertebrate and mammalian systems, and prospects for further advances in each.
Collapse
Affiliation(s)
- Samuel Liu
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Kellianne D. Alexander
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Michael M. Francis
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Program in Neuroscience, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| |
Collapse
|
11
|
Tomita-Naito S, Sulekh S, Yoo SK. Insidious chromatin change with a propensity to exhaust intestinal stem cells during aging. iScience 2024; 27:110793. [PMID: 39371074 PMCID: PMC11452737 DOI: 10.1016/j.isci.2024.110793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 06/25/2024] [Accepted: 08/19/2024] [Indexed: 10/08/2024] Open
Abstract
During aging, tissue stem cells can demonstrate two opposing phenotypes of tissue homeostasis disruption: proliferation and exhaustion. Stem cells can exhaust as a result of excessive cell proliferation or independently of cell proliferation. There are many silent changes in chromatin structures and gene expression that are not necessarily reflected in manifested phenotypes during aging. Here through analyses of chromatin accessibility and gene expression in intestinal progenitor cells during aging, we discovered changes of chromatin accessibility and gene expression that have a propensity to exhaust intestinal stem cells (ISCs). During aging, Trithorax-like (Trl) target genes, ced-6 and ci, close their chromatin structures and decrease their expression in intestinal progenitor cells. Inhibition of Trl, ced-6, or ci exhausts ISCs. This study provides new insight into changes of chromatin accessibility and gene expression that have a potential to exhaust ISCs during aging.
Collapse
Affiliation(s)
- Saki Tomita-Naito
- Laboratory for Homeodynamics, RIKEN BDR, Kobe, Japan
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Shivakshi Sulekh
- Laboratory for Homeodynamics, RIKEN BDR, Kobe, Japan
- Division of Developmental Biology and Regenerative Medicine, Kobe University, Kobe, Japan
| | - Sa Kan Yoo
- Laboratory for Homeodynamics, RIKEN BDR, Kobe, Japan
- Division of Developmental Biology and Regenerative Medicine, Kobe University, Kobe, Japan
- Physiological Genetics Laboratory, RIKEN CPR, Kobe, Japan
| |
Collapse
|
12
|
de Deus JL, Faborode OS, Nandi S. Synaptic Pruning by Microglia: Lessons from Genetic Studies in Mice. Dev Neurosci 2024:1-21. [PMID: 39265565 DOI: 10.1159/000541379] [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: 06/14/2024] [Accepted: 09/06/2024] [Indexed: 09/14/2024] Open
Abstract
BACKGROUND Neural circuits are subjected to refinement throughout life. The dynamic addition and elimination (pruning) of synapses are necessary for maturation of neural circuits and synaptic plasticity. Due to their phagocytic nature, microglia have been considered as the primary mediators of synaptic pruning. Synaptic pruning can strengthen an active synapse by removing excess weaker synapses during development. Inappropriate synaptic pruning can often influence a disease outcome or an injury response. SUMMARY This review offers a focused discussion on microglial roles in synaptic pruning, based on the evidence gathered from genetic manipulations in mice. Genetically labeled microglia and synapses often allow assessment of their interactions in real time. Further manipulations involving synaptically localized molecules, neuronally or glial-derived diffusible factors, and their respective cognate receptors in microglia provide critical evidence in support of a direct role of microglia in synaptic pruning. KEY MESSAGE We discuss microglial contact-dependent "eat-me," "don't-eat-me," and "find-me" signals, as well as recently identified noncontact pruning, under the contexts of neural circuit, brain region, developmental window, and an injury or a disease state.
Collapse
Affiliation(s)
- Junia Lara de Deus
- Department of Anatomy, Howard University College of Medicine, Washington, DC, USA
| | | | - Sayan Nandi
- Department of Anatomy, Howard University College of Medicine, Washington, DC, USA
| |
Collapse
|
13
|
Sung HH, Li H, Huang YC, Ai CL, Hsieh MY, Jan HM, Peng YJ, Lin HY, Yeh CH, Lin SY, Yeh CY, Cheng YJ, Khoo KH, Lin CH, Chien CT. Galectins induced from hemocytes bridge phosphatidylserine and N-glycosylated Drpr/CED-1 receptor during dendrite pruning. Nat Commun 2024; 15:7402. [PMID: 39191750 DOI: 10.1038/s41467-024-51581-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 08/12/2024] [Indexed: 08/29/2024] Open
Abstract
During neuronal pruning, phagocytes engulf shed cellular debris to avoid inflammation and maintain tissue homeostasis. How phagocytic receptors recognize degenerating neurites had been unclear. Here, we identify two glucosyltransferases Alg8 and Alg10 of the N-glycosylation pathway required for dendrite fragmentation and clearance through genetic screen. The scavenger receptor Draper (Drpr) is N-glycosylated with complex- or hybrid-type N-glycans that interact specifically with galectins. We also identify the galectins Crouching tiger (Ctg) and Hidden dragon (Hdg) that interact with N-glycosylated Drpr and function in dendrite pruning via the Drpr pathway. Ctg and Hdg are required in hemocytes for expression and function, and are induced during dendrite injury to localize to injured dendrites through specific interaction with exposed phosphatidylserine (PS) on the surface membrane of injured dendrites. Thus, the galectins Ctg and Hdg bridge the interaction between PS and N-glycosylated Drpr, leading to the activation of phagocytosis.
Collapse
Affiliation(s)
- Hsin-Ho Sung
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Hsun Li
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Chun Huang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chun-Lu Ai
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Ming-Yen Hsieh
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hau-Ming Jan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Yu-Ju Peng
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hsien-Ya Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chih-Hsuan Yeh
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Shu-Yu Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chun-Yen Yeh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Ying-Ju Cheng
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Kay-Hooi Khoo
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chun-Hung Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Cheng-Ting Chien
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
- Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan.
| |
Collapse
|
14
|
Harders RH, Morthorst TH, Landgrebe LE, Lande AD, Fuglsang MS, Mortensen SB, Feteira-Montero V, Jensen HH, Wesseltoft JB, Olsen A. CED-6/GULP and components of the clathrin-mediated endocytosis machinery act redundantly to correctly display CED-1 on the cell membrane in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2024; 14:jkae088. [PMID: 38696649 PMCID: PMC11228867 DOI: 10.1093/g3journal/jkae088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/03/2024] [Accepted: 04/16/2024] [Indexed: 05/04/2024]
Abstract
CED-1 (cell death abnormal) is a transmembrane receptor involved in the recognition of "eat-me" signals displayed on the surface of apoptotic cells and thus central for the subsequent engulfment of the cell corpse in Caenorhabditis elegans. The roles of CED-1 in engulfment are well established, as are its downstream effectors. The latter include the adapter protein CED-6/GULP and the ATP-binding cassette family homolog CED-7. However, how CED-1 is maintained on the plasma membrane in the absence of engulfment is currently unknown. Here, we show that CED-6 and CED-7 have a novel role in maintaining CED-1 correctly on the plasma membrane. We propose that the underlying mechanism is via endocytosis as CED-6 and CED-7 act redundantly with clathrin and its adaptor, the Adaptor protein 2 complex, in ensuring correct CED-1 localization. In conclusion, CED-6 and CED-7 impact other cellular processes than engulfment of apoptotic cells.
Collapse
Affiliation(s)
- Rikke Hindsgaul Harders
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg, DK-9220, Denmark
| | - Tine H Morthorst
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, Aarhus, DK-8000, Denmark
| | - Line E Landgrebe
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, Aarhus, DK-8000, Denmark
| | - Anna D Lande
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, Aarhus, DK-8000, Denmark
| | - Marie Sikjær Fuglsang
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, Aarhus, DK-8000, Denmark
| | - Stine Bothilde Mortensen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg, DK-9220, Denmark
| | - Verónica Feteira-Montero
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg, DK-9220, Denmark
| | - Helene Halkjær Jensen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg, DK-9220, Denmark
| | - Jonas Bruhn Wesseltoft
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg, DK-9220, Denmark
| | - Anders Olsen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg, DK-9220, Denmark
| |
Collapse
|
15
|
Nelson N, Vita DJ, Broadie K. Experience-dependent glial pruning of synaptic glomeruli during the critical period. Sci Rep 2024; 14:9110. [PMID: 38643298 PMCID: PMC11032375 DOI: 10.1038/s41598-024-59942-3] [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: 02/14/2024] [Accepted: 04/16/2024] [Indexed: 04/22/2024] Open
Abstract
Critical periods are temporally-restricted, early-life windows when sensory experience remodels synaptic connectivity to optimize environmental input. In the Drosophila juvenile brain, critical period experience drives synapse elimination, which is transiently reversible. Within olfactory sensory neuron (OSN) classes synapsing onto single projection neurons extending to brain learning/memory centers, we find glia mediate experience-dependent pruning of OSN synaptic glomeruli downstream of critical period odorant exposure. We find glial projections infiltrate brain neuropil in response to critical period experience, and use Draper (MEGF10) engulfment receptors to prune synaptic glomeruli. Downstream, we find antagonistic Basket (JNK) and Puckered (DUSP) signaling is required for the experience-dependent translocation of activated Basket into glial nuclei. Dependent on this signaling, we find critical period experience drives expression of the F-actin linking signaling scaffold Cheerio (FLNA), which is absolutely essential for the synaptic glomeruli pruning. We find Cheerio mediates experience-dependent regulation of the glial F-actin cytoskeleton for critical period remodeling. These results define a sequential pathway for experience-dependent brain synaptic glomeruli pruning in a strictly-defined critical period; input experience drives neuropil infiltration of glial projections, Draper/MEGF10 receptors activate a Basket/JNK signaling cascade for transcriptional activation, and Cheerio/FLNA induction regulates the glial actin cytoskeleton to mediate targeted synapse phagocytosis.
Collapse
Affiliation(s)
- Nichalas Nelson
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA
| | - Dominic J Vita
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Department of Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
| |
Collapse
|
16
|
Lindsay-Mosher N, Lusk S, Pearson BJ. Planarians require ced-12/elmo-1 to clear dead cells by excretion through the gut. Cell Rep 2024; 43:113621. [PMID: 38165802 DOI: 10.1016/j.celrep.2023.113621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 10/13/2023] [Accepted: 12/08/2023] [Indexed: 01/04/2024] Open
Abstract
Cell corpse removal is a critical component of both development and homeostasis throughout the animal kingdom. Extensive research has revealed many of the mechanisms involved in corpse removal, typically involving engulfment and digestion by another cell; however, the dynamics of cell corpse clearance in adult tissues remain unclear. Here, we track cell death in the adult planarian Schmidtea mediterranea and find that, following light-induced cell death, pigment cell corpses transit to the gut and are excreted from the animal. Gut phagocytes, previously only known to phagocytose food, are required for pigment cells to enter the gut lumen. Finally, we show that the planarian ortholog of ced-12/engulfment and cell motility (ELMO) is required for corpse phagocytosis and removal through the gut. In total, we present a mechanism of cell clearance in an adult organism involving transit of dead cells to the gut, transport into the gut by phagocytes, and physical excretion of debris.
Collapse
Affiliation(s)
- Nicole Lindsay-Mosher
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON, Canada
| | - Sarah Lusk
- Papé Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Bret J Pearson
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON, Canada; Papé Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA.
| |
Collapse
|
17
|
Guangming G, Mei C, Qinfeng Y, Xiang G, Chenchen Z, Qingyuan S, Wei X, Junhua G. Neurexin and neuroligins jointly regulate synaptic degeneration at the Drosophila neuromuscular junction based on TEM studies. Front Cell Neurosci 2023; 17:1257347. [PMID: 38026694 PMCID: PMC10646337 DOI: 10.3389/fncel.2023.1257347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/12/2023] [Indexed: 12/01/2023] Open
Abstract
The Drosophila larval neuromuscular junction (NMJ) is a well-known model system and is often used to study synapse development. Here, we show synaptic degeneration at NMJ boutons, primarily based on transmission electron microscopy (TEM) studies. When degeneration starts, the subsynaptic reticulum (SSR) swells, retracts and folds inward, and the residual SSR then degenerates into a disordered, thin or linear membrane. The axon terminal begins to degenerate from the central region, and the T-bar detaches from the presynaptic membrane with clustered synaptic vesicles to accelerate large-scale degeneration. There are two degeneration modes for clear synaptic vesicles. In the first mode, synaptic vesicles without actin filaments degenerate on the membrane with ultrafine spots and collapse and disperse to form an irregular profile with dark ultrafine particles. In the second mode, clear synaptic vesicles with actin filaments degenerate into dense synaptic vesicles, form irregular dark clumps without a membrane, and collapse and disperse to form an irregular profile with dark ultrafine particles. Last, all residual membranes in NMJ boutons degenerate into a linear shape, and all the residual elements in axon terminals degenerate and eventually form a cluster of dark ultrafine particles. Swelling and retraction of the SSR occurs prior to degradation of the axon terminal, which degenerates faster and with more intensity than the SSR. NMJ bouton degeneration occurs under normal physiological conditions but is accelerated in Drosophila neurexin (dnrx) dnrx273, Drosophila neuroligin (dnlg) dnlg1 and dnlg4 mutants and dnrx83;dnlg3 and dnlg2;dnlg3 double mutants, which suggests that both neurexin and neuroligins play a vital role in preventing synaptic degeneration.
Collapse
Affiliation(s)
- Gan Guangming
- School of Medicine, Southeast University, Nanjing, Jiangsu, China
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
| | - Chen Mei
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
| | - Yu Qinfeng
- School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Gao Xiang
- School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Zhang Chenchen
- School of Medicine, Southeast University, Nanjing, Jiangsu, China
| | - Sheng Qingyuan
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
| | - Xie Wei
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
- The Collaborative Innovation Center for Brain Science, Southeast University, Nanjing, Jiangsu, China
| | - Geng Junhua
- School of Life Science and Technology, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China
- Shenzhen Research Institute of Southeast University, Shenzhen, Guangdong, China
| |
Collapse
|
18
|
Heron R, Amato C, Wood W, Davidson AJ. Understanding the diversity and dynamics of in vivo efferocytosis: Insights from the fly embryo. Immunol Rev 2023; 319:27-44. [PMID: 37589239 PMCID: PMC10952863 DOI: 10.1111/imr.13266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/18/2023] [Indexed: 08/18/2023]
Abstract
The clearance of dead and dying cells, termed efferocytosis, is a rapid and efficient process and one that is critical for organismal health. The extraordinary speed and efficiency with which dead cells are detected and engulfed by immune cells within tissues presents a challenge to researchers who wish to unravel this fascinating process, since these fleeting moments of uptake are almost impossible to catch in vivo. In recent years, the fruit fly (Drosophila melanogaster) embryo has emerged as a powerful model to circumvent this problem. With its abundance of dying cells, specialist phagocytes and relative ease of live imaging, the humble fly embryo provides a unique opportunity to catch and study the moment of cell engulfment in real-time within a living animal. In this review, we explore the recent advances that have come from studies in the fly, and how live imaging and genetics have revealed a previously unappreciated level of diversity in the efferocytic program. A variety of efferocytic strategies across the phagocytic cell population ensure efficient and rapid clearance of corpses wherever death is encountered within the varied and complex setting of a multicellular living organism.
Collapse
Affiliation(s)
- Rosalind Heron
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Clelia Amato
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Will Wood
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Andrew J. Davidson
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
- School of Cancer SciencesWolfson Wohl Cancer Research Centre, University of GlasgowGlasgowUK
| |
Collapse
|
19
|
Seong KH, Uemura T, Kang S. Road to sexual maturity: Behavioral event schedule from eclosion to first mating in each sex of Drosophila melanogaster. iScience 2023; 26:107502. [PMID: 37636050 PMCID: PMC10448111 DOI: 10.1016/j.isci.2023.107502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/24/2023] [Accepted: 07/26/2023] [Indexed: 08/29/2023] Open
Abstract
Animals achieve their first mating through the process of sexual maturation. This study examined the precise and detailed timing of a series of behavioral events, including wing expansion, first feeding, first excretion, and courtship, during sexual maturation from eclosion to first mating in D. melanogaster. We found that the time of first mating is genetically invariant and is not affected by light/dark cycle or food intake after eclosion. We also found sexual dimorphism in locomotor activity after eclosion, with females increasing locomotor activity earlier than males. In addition, we found a time rapidly changing from extremely low to high sexual activity in males post eclosion (named "drastic male courtship arousal" or DMCA). These behavioral traits leading up to the first mating could serve as clear indicators of sexual maturation and establish precisely timed developmental landmarks to explore further the mechanisms underlying the integration of behavioral and physiological sexual maturation.
Collapse
Affiliation(s)
- Ki-Hyeon Seong
- Department of Liberal Arts and Human Development, Kanagawa University of Human Services, 1-10-1 Heiseicho, Yokosuka, Kanagawa 238-8522, Japan
- Japan Agency for Medical Research and Development (AMED)-CREST, AMED, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Tadashi Uemura
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
- Center for Living Systems Information Science, Kyoto University, Kyoto 606-8501, Japan
- Japan Agency for Medical Research and Development (AMED)-CREST, AMED, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Siu Kang
- Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata 992-8510, Japan
- Japan Agency for Medical Research and Development (AMED)-CREST, AMED, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| |
Collapse
|
20
|
Park J, Chung WS. Astrocyte-dependent circuit remodeling by synapse phagocytosis. Curr Opin Neurobiol 2023; 81:102732. [PMID: 37247606 DOI: 10.1016/j.conb.2023.102732] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/30/2023] [Accepted: 05/03/2023] [Indexed: 05/31/2023]
Abstract
In the central nervous system, synaptic pruning, the removal of unnecessary synaptic contacts, is an essential process for proper circuit maturation in neurodevelopment as well as for synaptic homeostasis in the adult stage. Dysregulation of synaptic pruning can contribute to the initiation and progression of various mental disorders, such as schizophrenia and depression, as well as neurodegenerative diseases including Alzheimer's disease. In the past 15 years, pioneering works have demonstrated that different types of glial cells regulate the number of synapses by selectively eliminating them through phagocytic molecular machinery. Although a majority of findings have been focused on microglia, it is increasingly evident that astrocytes function as a critical player in activity-dependent synapse elimination in developing, adult, and diseased brains. In this review, we will discuss recent findings showing the mechanisms and physiological importance of astrocyte-mediated synapse elimination in controlling synapses and circuit homeostasis. We propose that astrocytes play dominant and non-redundant roles in eliminating synapses during the activity-dependent circuit remodeling processes that do not involve neuro-inflammation.
Collapse
Affiliation(s)
- Jungjoo Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
| | - Won-Suk Chung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
| |
Collapse
|
21
|
Wang Y, Zhang R, Huang S, Valverde PTT, Lobb-Rabe M, Ashley J, Venkatasubramanian L, Carrillo RA. Glial Draper signaling triggers cross-neuron plasticity in bystander neurons after neuronal cell death in Drosophila. Nat Commun 2023; 14:4452. [PMID: 37488133 PMCID: PMC10366216 DOI: 10.1038/s41467-023-40142-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 07/07/2023] [Indexed: 07/26/2023] Open
Abstract
Neuronal cell death and subsequent brain dysfunction are hallmarks of aging and neurodegeneration, but how the nearby healthy neurons (bystanders) respond to the death of their neighbors is not fully understood. In the Drosophila larval neuromuscular system, bystander motor neurons can structurally and functionally compensate for the loss of their neighbors by increasing their terminal bouton number and activity. We term this compensation as cross-neuron plasticity, and in this study, we demonstrate that the Drosophila engulfment receptor, Draper, and the associated kinase, Shark, are required for cross-neuron plasticity. Overexpression of the Draper-I isoform boosts cross-neuron plasticity, implying that the strength of plasticity correlates with Draper signaling. In addition, we find that functional cross-neuron plasticity can be induced at different developmental stages. Our work uncovers a role for Draper signaling in cross-neuron plasticity and provides insights into how healthy bystander neurons respond to the loss of their neighboring neurons.
Collapse
Affiliation(s)
- Yupu Wang
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA.
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 20147, USA.
| | - Ruiling Zhang
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Sihao Huang
- Program in Biochemistry and Molecular Biophysics, University of Chicago, Chicago, IL, 60637, USA
| | - Parisa Tajalli Tehrani Valverde
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Meike Lobb-Rabe
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA
| | - James Ashley
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
| | | | - Robert A Carrillo
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA.
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL, 60637, USA.
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.
| |
Collapse
|
22
|
Ji H, Wang B, Shen Y, Labib D, Lei J, Chen X, Sapar M, Boulanger A, Dura JM, Han C. The Drosophila chemokine-like Orion bridges phosphatidylserine and Draper in phagocytosis of neurons. Proc Natl Acad Sci U S A 2023; 120:e2303392120. [PMID: 37276397 PMCID: PMC10268242 DOI: 10.1073/pnas.2303392120] [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: 02/28/2023] [Accepted: 04/10/2023] [Indexed: 06/07/2023] Open
Abstract
Phagocytic clearance of degenerating neurons is triggered by "eat-me" signals exposed on the neuronal surface. The conserved neuronal eat-me signal phosphatidylserine (PS) and the engulfment receptor Draper (Drpr) mediate phagocytosis of degenerating neurons in Drosophila. However, how PS is recognized by Drpr-expressing phagocytes in vivo remains poorly understood. Using multiple models of dendrite degeneration, we show that the Drosophila chemokine-like protein Orion can bind to PS and is responsible for detecting PS exposure on neurons; it is supplied cell-non-autonomously to coat PS-exposing dendrites and to mediate interactions between PS and Drpr, thus enabling phagocytosis. As a result, the accumulation of Orion on neurons and on phagocytes produces opposite outcomes by potentiating and suppressing phagocytosis, respectively. Moreover, the Orion dosage is a key determinant of the sensitivity of phagocytes to PS exposed on neurons. Lastly, mutagenesis analyses show that the sequence motifs shared between Orion and human immunomodulatory proteins are important for Orion function. Thus, our results uncover a missing link in PS-mediated phagocytosis in Drosophila and imply conserved mechanisms of phagocytosis of neurons.
Collapse
Affiliation(s)
- Hui Ji
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Bei Wang
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Yifan Shen
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - David Labib
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Joyce Lei
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Xinchen Chen
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Maria Sapar
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Ana Boulanger
- Institute of Human Genetics (IGH), Univ Montpellier, CNRS, Montpellier34090, France
| | - Jean-Maurice Dura
- Institute of Human Genetics (IGH), Univ Montpellier, CNRS, Montpellier34090, France
| | - Chun Han
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| |
Collapse
|
23
|
Jindal DA, Leier HC, Salazar G, Foden AJ, Seitz EA, Wilkov AJ, Coutinho-Budd JC, Broihier HT. Early Draper-mediated glial refinement of neuropil architecture and synapse number in the Drosophila antennal lobe. Front Cell Neurosci 2023; 17:1166199. [PMID: 37333889 PMCID: PMC10272751 DOI: 10.3389/fncel.2023.1166199] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/15/2023] [Indexed: 06/20/2023] Open
Abstract
Glial phagocytic activity refines connectivity, though molecular mechanisms regulating this exquisitely sensitive process are incompletely defined. We developed the Drosophila antennal lobe as a model for identifying molecular mechanisms underlying glial refinement of neural circuits in the absence of injury. Antennal lobe organization is stereotyped and characterized by individual glomeruli comprised of unique olfactory receptor neuronal (ORN) populations. The antennal lobe interacts extensively with two glial subtypes: ensheathing glia wrap individual glomeruli, while astrocytes ramify considerably within them. Phagocytic roles for glia in the uninjured antennal lobe are largely unknown. Thus, we tested whether Draper regulates ORN terminal arbor size, shape, or presynaptic content in two representative glomeruli: VC1 and VM7. We find that glial Draper limits the size of individual glomeruli and restrains their presynaptic content. Moreover, glial refinement is apparent in young adults, a period of rapid terminal arbor and synapse growth, indicating that synapse addition and elimination occur simultaneously. Draper has been shown to be expressed in ensheathing glia; unexpectedly, we find it expressed at high levels in late pupal antennal lobe astrocytes. Surprisingly, Draper plays differential roles in ensheathing glia and astrocytes in VC1 and VM7. In VC1, ensheathing glial Draper plays a more significant role in shaping glomerular size and presynaptic content; while in VM7, astrocytic Draper plays the larger role. Together, these data indicate that astrocytes and ensheathing glia employ Draper to refine circuitry in the antennal lobe before the terminal arbors reach their mature form and argue for local heterogeneity of neuron-glia interactions.
Collapse
Affiliation(s)
- Darren A. Jindal
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Hans C. Leier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Gabriela Salazar
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Alexander J. Foden
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Elizabeth A. Seitz
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Abigail J. Wilkov
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Jaeda C. Coutinho-Budd
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Heather T. Broihier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| |
Collapse
|
24
|
Wang Y, Zhang R, Huang S, Valverde PTT, Lobb-Rabe M, Ashley J, Venkatasubramanian L, Carrillo RA. Glial Draper signaling triggers cross-neuron plasticity in bystander neurons after neuronal cell death. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.09.536190. [PMID: 37090512 PMCID: PMC10120647 DOI: 10.1101/2023.04.09.536190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Neuronal cell death and subsequent brain dysfunction are hallmarks of aging and neurodegeneration, but how the nearby healthy neurons (bystanders) respond to the cell death of their neighbors is not fully understood. In the Drosophila larval neuromuscular system, bystander motor neurons can structurally and functionally compensate for the loss of their neighbors by increasing their axon terminal size and activity. We termed this compensation as cross-neuron plasticity, and in this study, we demonstrated that the Drosophila engulfment receptor, Draper, and the associated kinase, Shark, are required in glial cells. Surprisingly, overexpression of the Draper-I isoform boosts cross-neuron plasticity, implying that the strength of plasticity correlates with Draper signaling. Synaptic plasticity normally declines as animals age, but in our system, functional cross-neuron plasticity can be induced at different time points, whereas structural cross-neuron plasticity can only be induced at early stages. Our work uncovers a novel role for glial Draper signaling in cross-neuron plasticity that may enhance nervous system function during neurodegeneration and provides insights into how healthy bystander neurons respond to the loss of their neighboring neurons.
Collapse
|
25
|
Truman JW, Riddiford LM. Drosophila postembryonic nervous system development: a model for the endocrine control of development. Genetics 2023; 223:iyac184. [PMID: 36645270 PMCID: PMC9991519 DOI: 10.1093/genetics/iyac184] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/13/2022] [Indexed: 01/17/2023] Open
Abstract
During postembryonic life, hormones, including ecdysteroids, juvenile hormones, insulin-like peptides, and activin/TGFβ ligands act to transform the larval nervous system into an adult version, which is a fine-grained mosaic of recycled larval neurons and adult-specific neurons. Hormones provide both instructional signals that make cells competent to undergo developmental change and timing cues to evoke these changes across the nervous system. While touching on all the above hormones, our emphasis is on the ecdysteroids, ecdysone and 20-hydroxyecdysone (20E). These are the prime movers of insect molting and metamorphosis and are involved in all phases of nervous system development, including neurogenesis, pruning, arbor outgrowth, and cell death. Ecdysteroids appear as a series of steroid peaks that coordinate the larval molts and the different phases of metamorphosis. Each peak directs a stereotyped cascade of transcription factor expression. The cascade components then direct temporal programs of effector gene expression, but the latter vary markedly according to tissue and life stage. The neurons read the ecdysteroid titer through various isoforms of the ecdysone receptor, a nuclear hormone receptor. For example, at metamorphosis the pruning of larval neurons is mediated through the B isoforms, which have strong activation functions, whereas subsequent outgrowth is mediated through the A isoform through which ecdysteroids play a permissive role to allow local tissue interactions to direct outgrowth. The major circulating ecdysteroid can also change through development. During adult development ecdysone promotes early adult patterning and differentiation while its metabolite, 20E, later evokes terminal adult differentiation.
Collapse
Affiliation(s)
- James W Truman
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
| | - Lynn M Riddiford
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
| |
Collapse
|
26
|
Marmor-Kollet N, Berkun V, Cummings G, Keren-Shaul H, David E, Addadi Y, Schuldiner O. Actin-dependent astrocytic infiltration is a key step for axon defasciculation during remodeling. Cell Rep 2023; 42:112117. [PMID: 36790930 PMCID: PMC9989824 DOI: 10.1016/j.celrep.2023.112117] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 10/17/2022] [Accepted: 01/28/2023] [Indexed: 02/16/2023] Open
Abstract
Astrocytes are essential for synapse formation, maturation, and plasticity; however, their function during developmental neuronal remodeling is largely unknown. To identify astrocytic molecules required for axon pruning of mushroom body (MB) γ neurons in Drosophila, we profiled astrocytes before (larva) and after (adult) remodeling. Focusing on genes enriched in larval astrocytes, we identified 12 astrocytic genes that are required for axon pruning, including the F-actin regulators Actin-related protein 2/3 complex, subunit 1 (Arpc1) and formin3 (form3). Interestingly, perturbing astrocytic actin dynamics does not affect their gross morphology, migration, or transforming growth factor β (TGF-β) secretion. In contrast, actin dynamics is required for astrocyte infiltration into the axon bundle at the onset of pruning. Remarkably, decreasing axonal adhesion facilitates infiltration by Arpc1 knockdown (KD) astrocytes and promotes axon pruning. Conversely, increased axonal adhesion reduces lobe infiltration by wild-type (WT) astrocytes. Together, our findings suggest that actin-dependent astrocytic infiltration is a key step in axon pruning, thus promoting our understanding of neuron-glia interactions during remodeling.
Collapse
Affiliation(s)
- Neta Marmor-Kollet
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Victoria Berkun
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Gideon Cummings
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Hadas Keren-Shaul
- Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eyal David
- Department of Immunology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yoseph Addadi
- Weizmann Institute of Science, Life Sciences Core Facilities, Rehovot 7610001, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 7610001, Israel; Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 7610001, Israel.
| |
Collapse
|
27
|
Krämer R, Wolterhoff N, Galic M, Rumpf S. Developmental pruning of sensory neurites by mechanical tearing in Drosophila. J Cell Biol 2023; 222:213805. [PMID: 36648440 PMCID: PMC9856751 DOI: 10.1083/jcb.202205004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/24/2022] [Accepted: 01/04/2023] [Indexed: 01/18/2023] Open
Abstract
Mechanical forces actively shape cells during development, but little is known about their roles during neuronal morphogenesis. Developmental neurite pruning, a critical circuit specification mechanism, often involves neurite abscission at predetermined sites by unknown mechanisms. Pruning of Drosophila sensory neuron dendrites during metamorphosis is triggered by the hormone ecdysone, which induces local disassembly of the dendritic cytoskeleton. Subsequently, dendrites are severed at positions close to the soma by an unknown mechanism. We found that ecdysone signaling causes the dendrites to become mechanically fragile. Severing occurs during periods of increased pupal morphogenetic tissue movements, which exert mechanical forces on the destabilized dendrites. Tissue movements and dendrite severing peak during pupal ecdysis, a period of strong abdominal contractions, and abolishing ecdysis causes non-cell autonomous dendrite pruning defects. Thus, our data establish mechanical tearing as a novel mechanism during neurite pruning.
Collapse
Affiliation(s)
- Rafael Krämer
- https://ror.org/00pd74e08Institute for Neurobiology, University of Münster, Münster, Germany
| | - Neele Wolterhoff
- https://ror.org/00pd74e08Institute for Neurobiology, University of Münster, Münster, Germany
| | - Milos Galic
- Institute of Medical Physics and Biophysics, University of Münster, Münster, Germany
| | - Sebastian Rumpf
- https://ror.org/00pd74e08Institute for Neurobiology, University of Münster, Münster, Germany
| |
Collapse
|
28
|
Lin S. The making of the Drosophila mushroom body. Front Physiol 2023; 14:1091248. [PMID: 36711013 PMCID: PMC9880076 DOI: 10.3389/fphys.2023.1091248] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 01/02/2023] [Indexed: 01/14/2023] Open
Abstract
The mushroom body (MB) is a computational center in the Drosophila brain. The intricate neural circuits of the mushroom body enable it to store associative memories and process sensory and internal state information. The mushroom body is composed of diverse types of neurons that are precisely assembled during development. Tremendous efforts have been made to unravel the molecular and cellular mechanisms that build the mushroom body. However, we are still at the beginning of this challenging quest, with many key aspects of mushroom body assembly remaining unexplored. In this review, I provide an in-depth overview of our current understanding of mushroom body development and pertinent knowledge gaps.
Collapse
|
29
|
Sakakibara Y, Yamashiro R, Chikamatsu S, Hirota Y, Tsubokawa Y, Nishijima R, Takei K, Sekiya M, Iijima KM. Drosophila Toll-9 is induced by aging and neurodegeneration to modulate stress signaling and its deficiency exacerbates tau-mediated neurodegeneration. iScience 2023; 26:105968. [PMID: 36718365 PMCID: PMC9883205 DOI: 10.1016/j.isci.2023.105968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/06/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Drosophila Toll-9 is most closely related to mammalian Toll-like receptors; however, physiological functions of Toll-9 remain elusive. We examined the roles of Toll-9 in fly brains in aging and neurodegeneration. Toll-9 mRNA levels were increased in aged fly heads accompanied by activation of nuclear factor-kappa B (NF-kB) and stress-activated protein kinase (SAPK) signaling, and many of these changes were modulated by Toll-9 in glial cells. The loss of Toll-9 did not affect lifespan or brain integrity, whereas it exacerbated hydrogen peroxide-induced lethality. Toll-9 expression was also induced by nerve injury but did not affect acute stress response or glial engulfment activity, suggesting Toll-9 may modulate subsequent neurodegeneration. In a fly tauopathy model, Toll-9 deficiency enhanced neurodegeneration and disease-related tau phosphorylation with reduced SAPK activity, and blocking SAPK enhanced tau phosphorylation and neurodegeneration. In sum, Toll-9 is induced upon aging and nerve injury and affects neurodegeneration by modulating stress kinase signaling.
Collapse
Affiliation(s)
- Yasufumi Sakakibara
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Risa Yamashiro
- Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Sachie Chikamatsu
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Yu Hirota
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan,Reseach Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Yoko Tsubokawa
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Risa Nishijima
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Kimi Takei
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Michiko Sekiya
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan,Corresponding author
| | - Koichi M. Iijima
- Department of Neurogenetics, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan,Corresponding author
| |
Collapse
|
30
|
Davis J, Kolaski E, Babcock DT. Vexed mutations promote degeneration of dopaminergic neurons through excessive activation of the innate immune response. NPJ Parkinsons Dis 2022; 8:147. [PMID: 36323700 PMCID: PMC9630459 DOI: 10.1038/s41531-022-00417-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/14/2022] [Indexed: 11/11/2022] Open
Abstract
The hallmark of Parkinson's disease (PD) is the loss of dopaminergic (DA) neurons in the brain. However, little is known about why DA neurons are selectively vulnerable to PD. We previously completed a screen identifying genes associated with the progressive degeneration of DA neurons. Here we describe the role of a previously uncharacterized gene, CG42339, in the loss of DA neurons using Drosophila Melanogaster. CG42339 mutants display a progressive loss of DA neurons and locomotor dysfunction, along with an accumulation of advanced glycation end products (AGEs) in the brain. Based on this phenotype, we refer to CG42339 as vexed. We demonstrate that vexed is specifically required within cortex glia to maintain neuronal viability. Loss of vexed function results in excessive activation of the innate immune response in the brain, leading to loss of DA neurons. We show that activation of the innate immune response leads to increased nitric oxide signaling and accumulation of AGEs, which ultimately result in neurodegeneration. These results provide further insight into the relationship between the role of the immune response in the central nervous system and how this impacts neuronal viability.
Collapse
Affiliation(s)
- Jacinta Davis
- grid.259029.50000 0004 1936 746XDepartment of Biological Sciences, Lehigh University, Bethlehem, PA USA
| | - Elizabeth Kolaski
- grid.259029.50000 0004 1936 746XDepartment of Biological Sciences, Lehigh University, Bethlehem, PA USA
| | - Daniel T. Babcock
- grid.259029.50000 0004 1936 746XDepartment of Biological Sciences, Lehigh University, Bethlehem, PA USA
| |
Collapse
|
31
|
Serizier SB, Peterson JS, McCall K. Non-autonomous cell death induced by the Draper phagocytosis receptor requires signaling through the JNK and SRC pathways. J Cell Sci 2022; 135:jcs250134. [PMID: 36177600 PMCID: PMC10658789 DOI: 10.1242/jcs.250134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/21/2022] [Indexed: 11/20/2022] Open
Abstract
The last step of cell death is cell clearance, a process critical for tissue homeostasis. For efficient cell clearance to occur, phagocytes and dead cells need to reciprocally signal to each other. One important phenomenon that is under-investigated, however, is that phagocytes not only engulf corpses but contribute to cell death progression. The aims of this study were to determine how the phagocytic receptor Draper non-autonomously induces cell death, using the Drosophila ovary as a model system. We found that Draper, expressed in epithelial follicle cells, requires its intracellular signaling domain to kill the adjacent nurse cell population. Kinases Src42A, Shark and JNK (Bsk) were required for Draper-induced nurse cell death. Signs of nurse cell death occurred prior to apparent engulfment and required the caspase Dcp-1, indicating that it uses a similar apoptotic pathway to starvation-induced cell death. These findings indicate that active signaling by Draper is required to kill nurse cells via the caspase Dcp-1, providing novel insights into mechanisms of phagoptosis driven by non-professional phagocytes.
Collapse
Affiliation(s)
- Sandy B. Serizier
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
- Program in Molecular Biology, Cell Biology, and Biochemistry, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Jeanne S. Peterson
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Kimberly McCall
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
- Program in Molecular Biology, Cell Biology, and Biochemistry, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| |
Collapse
|
32
|
Almazán A, Çevrim Ç, Musser JM, Averof M, Paris M. Crustacean leg regeneration restores complex microanatomy and cell diversity. SCIENCE ADVANCES 2022; 8:eabn9823. [PMID: 36001670 PMCID: PMC9401613 DOI: 10.1126/sciadv.abn9823] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Animals can regenerate complex organs, yet this process frequently results in imprecise replicas of the original structure. In the crustacean Parhyale, embryonic and regenerating legs differ in gene expression dynamics but produce apparently similar mature structures. We examine the fidelity of Parhyale leg regeneration using complementary approaches to investigate microanatomy, sensory function, cellular composition, and cell molecular profiles. We find that regeneration precisely replicates the complex microanatomy and spatial distribution of external sensory organs and restores their sensory function. Single-nuclei sequencing shows that regenerated and uninjured legs are indistinguishable in terms of cell-type composition and transcriptional profiles. This remarkable fidelity highlights the ability of organisms to achieve identical outcomes via distinct processes.
Collapse
Affiliation(s)
- Alba Almazán
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique (CNRS), École Normale Supérieure de Lyon and Université Claude Bernard Lyon 1, 69007 Lyon, France
| | - Çağrı Çevrim
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique (CNRS), École Normale Supérieure de Lyon and Université Claude Bernard Lyon 1, 69007 Lyon, France
| | - Jacob M. Musser
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Michalis Averof
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique (CNRS), École Normale Supérieure de Lyon and Université Claude Bernard Lyon 1, 69007 Lyon, France
| | - Mathilde Paris
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique (CNRS), École Normale Supérieure de Lyon and Université Claude Bernard Lyon 1, 69007 Lyon, France
| |
Collapse
|
33
|
Boulanger A, Dura JM. Neuron-glia crosstalk in neuronal remodeling and degeneration: Neuronal signals inducing glial cell phagocytic transformation in Drosophila. Bioessays 2022; 44:e2100254. [PMID: 35315125 DOI: 10.1002/bies.202100254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 11/09/2022]
Abstract
Neuronal remodeling is a conserved mechanism that eliminates unwanted neurites and can include the loss of cell bodies. In these processes, a key role for glial cells in events from synaptic pruning to neuron elimination has been clearly identified in the last decades. Signals sent from dying neurons or neurites to be removed are received by appropriate glial cells. After receiving these signals, glial cells infiltrate degenerating sites and then, engulf and clear neuronal debris through phagocytic mechanisms. There are few identified or proposed signals and receptors involved in neuron-glia crosstalk, which induces the transformation of glial cells to phagocytes during neuronal remodeling in Drosophila. Many of these signaling pathways are conserved in mammals. Here, we particularly emphasize the role of Orion, a recently identified neuronal CX3 C chemokine-like secreted protein, which induces astrocyte infiltration and engulfment during mushroom body neuronal remodeling. Although, chemokine signaling was not described previously in insects we propose that chemokine-like involvement in neuron/glial cell interaction is an evolutionarily ancient mechanism.
Collapse
Affiliation(s)
- Ana Boulanger
- IGH, Université de Montpellier, CNRS, Montpellier, France
| | | |
Collapse
|
34
|
Liu KE, Raymond MH, Ravichandran KS, Kucenas S. Clearing Your Mind: Mechanisms of Debris Clearance After Cell Death During Neural Development. Annu Rev Neurosci 2022; 45:177-198. [PMID: 35226828 PMCID: PMC10157384 DOI: 10.1146/annurev-neuro-110920-022431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurodevelopment and efferocytosis have fascinated scientists for decades. How an organism builds a nervous system that is precisely tuned for efficient behaviors and survival and how it simultaneously manages constant somatic cell turnover are complex questions that have resulted in distinct fields of study. Although neurodevelopment requires the overproduction of cells that are subsequently pruned back, very few studies marry these fields to elucidate the cellular and molecular mechanisms that drive nervous system development through the lens of cell clearance. In this review, we discuss these fields to highlight exciting areas of future synergy. We first review neurodevelopment from the perspective of overproduction and subsequent refinement and then discuss who clears this developmental debris and the mechanisms that control these events. We then end with how a more deliberate merger of neurodevelopment and efferocytosis could reframe our understanding of homeostasis and disease and discuss areas of future study. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Kendra E Liu
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA
| | - Michael H Raymond
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Center for Clearance, University of Virginia, Charlottesville, Virginia, USA
| | - Kodi S Ravichandran
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Center for Clearance, University of Virginia, Charlottesville, Virginia, USA.,Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA.,VIB-UGent Center for Inflammation Research and the Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Sarah Kucenas
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA.,Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| |
Collapse
|
35
|
Bindhani B, Maity S, Chakrabarti I, Saha SK. Roles of matrix metalloproteinases in development, immunology, and ovulation in fruit Fly (Drosophila). ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2022; 109:e21849. [PMID: 34779010 DOI: 10.1002/arch.21849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/17/2021] [Accepted: 10/21/2021] [Indexed: 06/13/2023]
Abstract
Matrix metalloproteinase (MMP), a protease enzyme, participates in proteolytic cleavage of extracellular matrix proteins from Drosophila and mammals. But, recent studies have revealed other physiologically important roles of MMP in Drosophila. MMP contributes to cardioblast movement and distribution of collagen proteins during cardiogenesis in developing Drosophila. Tissue remodeling, especially tracheal development is also maintained by MMP. MMP regulates certain immunological functions in Drosophila such as wound repairing, plasmatocyte assemblage at the injured site of the basement membrane and glial response to axon degeneration in Drosophila nervous system. But, the contribution of MMP to tumor formation and metastasis in Drosophila has made it an interesting topic among researchers. Ovulation and egg laying are also found to be affected positively by MMP in Drosophila.
Collapse
Affiliation(s)
- Banani Bindhani
- Department of Zoology, Dinabandhu Andrews College (affiliated to University of Calcutta), Kolkata, West Bengal, India
| | - Sulagna Maity
- Department of Zoology, Dinabandhu Andrews College (affiliated to University of Calcutta), Kolkata, West Bengal, India
| | - Ipsit Chakrabarti
- Department of Zoology, Dinabandhu Andrews College (affiliated to University of Calcutta), Kolkata, West Bengal, India
| | - Samir Kumar Saha
- Department of Zoology, West Bengal State University, Barasat, Kolkata, West Bengal, India
| |
Collapse
|
36
|
Zheng Q, Gao N, Sun Q, Li X, Wang Y, Xiao H. bfc, a novel serpent co-factor for the expression of croquemort, regulates efferocytosis in Drosophila melanogaster. PLoS Genet 2021; 17:e1009947. [PMID: 34860835 PMCID: PMC8673676 DOI: 10.1371/journal.pgen.1009947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 12/15/2021] [Accepted: 11/15/2021] [Indexed: 01/01/2023] Open
Abstract
Efferocytosis is the process by which phagocytes recognize, engulf, and digest (or clear) apoptotic cells during development. Impaired efferocytosis is associated with developmental defects and autoimmune diseases. In Drosophila melanogaster, recognition of apoptotic cells requires phagocyte surface receptors, including the scavenger receptor CD36-related protein, Croquemort (Crq, encoded by crq). In fact, Crq expression is upregulated in the presence of apoptotic cells, as well as in response to excessive apoptosis. Here, we identified a novel gene bfc (booster for croquemort), which plays a role in efferocytosis, specifically the regulation of the crq expression. We found that Bfc protein interacts with the zinc finger domain of the GATA transcription factor Serpent (Srp), to enhance its direct binding to the crq promoter; thus, they function together in regulating crq expression and efferocytosis. Overall, we show that Bfc serves as a Srp co-factor to upregulate the transcription of the crq encoded receptor, and consequently boosts macrophage efferocytosis in response to excessive apoptosis. Therefore, this study clarifies how phagocytes integrate apoptotic cell signals to mediate efferocytosis.
Collapse
Affiliation(s)
- Qian Zheng
- College of Life Sciences, Shaanxi Normal University, Xi’an, China
| | - Ning Gao
- College of Life Sciences, Shaanxi Normal University, Xi’an, China
| | - Qiling Sun
- College of Life Sciences, Shaanxi Normal University, Xi’an, China
| | - Xiaowen Li
- College of Life Sciences, Shaanxi Normal University, Xi’an, China
| | - Yanzhe Wang
- College of Life Sciences, Shaanxi Normal University, Xi’an, China
| | - Hui Xiao
- College of Life Sciences, Shaanxi Normal University, Xi’an, China
| |
Collapse
|
37
|
Faust TE, Gunner G, Schafer DP. Mechanisms governing activity-dependent synaptic pruning in the developing mammalian CNS. Nat Rev Neurosci 2021; 22:657-673. [PMID: 34545240 PMCID: PMC8541743 DOI: 10.1038/s41583-021-00507-y] [Citation(s) in RCA: 199] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2021] [Indexed: 02/08/2023]
Abstract
Almost 60 years have passed since the initial discovery by Hubel and Wiesel that changes in neuronal activity can elicit developmental rewiring of the central nervous system (CNS). Over this period, we have gained a more comprehensive picture of how both spontaneous neural activity and sensory experience-induced changes in neuronal activity guide CNS circuit development. Here we review activity-dependent synaptic pruning in the mammalian CNS, which we define as the removal of a subset of synapses, while others are maintained, in response to changes in neural activity in the developing nervous system. We discuss the mounting evidence that immune and cell-death molecules are important mechanistic links by which changes in neural activity guide the pruning of specific synapses, emphasizing the role of glial cells in this process. Finally, we discuss how these developmental pruning programmes may go awry in neurodevelopmental disorders of the human CNS, focusing on autism spectrum disorder and schizophrenia. Together, our aim is to give an overview of how the field of activity-dependent pruning research has evolved, led to exciting new questions and guided the identification of new, therapeutically relevant mechanisms that result in aberrant circuit development in neurodevelopmental disorders.
Collapse
Affiliation(s)
- Travis E Faust
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Georgia Gunner
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Dorothy P Schafer
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA.
| |
Collapse
|
38
|
Winkler B, Funke D, Benmimoun B, Spéder P, Rey S, Logan MA, Klämbt C. Brain inflammation triggers macrophage invasion across the blood-brain barrier in Drosophila during pupal stages. SCIENCE ADVANCES 2021; 7:eabh0050. [PMID: 34705495 PMCID: PMC8550232 DOI: 10.1126/sciadv.abh0050] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The nervous system is shielded from circulating immune cells by the blood-brain barrier (BBB). During infections and autoimmune diseases, macrophages can enter the brain where they participate in pathogen elimination but can also cause tissue damage. Here, we establish a Drosophila model to study macrophage invasion into the inflamed brain. We show that the immune deficiency (Imd) pathway, but not the Toll pathway, is responsible for attraction and invasion of hemolymph-borne macrophages across the BBB during pupal stages. Macrophage recruitment is mediated by glial, but not neuronal, induction of the Imd pathway through expression of Pvf2. Within the brain, macrophages can phagocytose synaptic material and reduce locomotor abilities and longevity. Similarly, we show that central nervous system infection by group B Streptococcus elicits macrophage recruitment in an Imd-dependent manner. This suggests that evolutionarily conserved inflammatory responses require a delicate balance between beneficial and detrimental activities.
Collapse
Affiliation(s)
- Bente Winkler
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Dominik Funke
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Billel Benmimoun
- Brain Plasticity in response to the Environment, Institut Pasteur, UMR3738 CNRS, 75015 Paris, France
| | - Pauline Spéder
- Brain Plasticity in response to the Environment, Institut Pasteur, UMR3738 CNRS, 75015 Paris, France
| | - Simone Rey
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Mary A. Logan
- Jungers Center for Neurosciences Research, Oregon Health and Science University, Portland, OR 97239, USA
| | - Christian Klämbt
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
- Corresponding author.
| |
Collapse
|
39
|
Losada-Pérez M, García-Guillén N, Casas-Tintó S. A novel injury paradigm in the central nervous system of adult Drosophila: molecular, cellular and functional aspects. Dis Model Mech 2021; 14:268374. [PMID: 34061177 PMCID: PMC8214735 DOI: 10.1242/dmm.044669] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 03/24/2021] [Indexed: 11/24/2022] Open
Abstract
The mammalian central nervous system (CNS) exhibits limited regenerative capacity and the mechanisms that mediate its regeneration are not fully understood. Here, we present a novel experimental design to damage the CNS by using a contusion injury paradigm. The design of this protocol allows the study of long-term and short-term cellular responses, including those of the CNS and the immune system, and of any implications regarding functional recovery. We demonstrate for the first time that adult Drosophilamelanogaster glial cells undergo spontaneous functional recovery following crush injury. This crush injury leads to an intermediate level of functional recovery after damage, which is ideal to screen for genes that facilitate or prevent the regeneration process. Here, we validate this model and analyse the immune responses of glial cells as a central regulator of functional regeneration. Additionally, we demonstrate that glial cells and macrophages contribute to functional regeneration through mechanisms involving the Jun N-terminal kinase (JNK) pathway and the Drosophila protein Draper (Drpr), characteristic of other neural injury paradigms. We show that macrophages are recruited to the injury site and are required for functional recovery. Further, we show that the proteins Grindelwald and Drpr in Drosophila glial cells mediate activation of JNK, and that expression of drpr is dependent on JNK activation. Finally, we link neuron-glial communication and the requirement of neuronal vesicular transport to regulation of the JNK pathway and functional recovery. This article has an associated First Person interview with the first author of the paper. Summary: Central nervous system crush injury paradigm in adult Drosophilamelanogaster is a suitable model to study the cellular events, and genetic pathways behind injury responses and functional regeneration. We describe the immune responses of glial cells, neurons and macrophages following injury, and the functional relevance of each response.
Collapse
Affiliation(s)
- María Losada-Pérez
- Instituto Cajal-CSIC, Department of Molecular, Cellular and Developmental Neurobiology, 28002 Madrid, Spain
| | - Nuria García-Guillén
- Instituto Cajal-CSIC, Department of Molecular, Cellular and Developmental Neurobiology, 28002 Madrid, Spain
| | - Sergio Casas-Tintó
- Instituto Cajal-CSIC, Department of Molecular, Cellular and Developmental Neurobiology, 28002 Madrid, Spain
| |
Collapse
|
40
|
Yin C, Peterman E, Rasmussen JP, Parrish JZ. Transparent Touch: Insights From Model Systems on Epidermal Control of Somatosensory Innervation. Front Cell Neurosci 2021; 15:680345. [PMID: 34135734 PMCID: PMC8200473 DOI: 10.3389/fncel.2021.680345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 04/28/2021] [Indexed: 12/28/2022] Open
Abstract
Somatosensory neurons (SSNs) densely innervate our largest organ, the skin, and shape our experience of the world, mediating responses to sensory stimuli including touch, pressure, and temperature. Historically, epidermal contributions to somatosensation, including roles in shaping innervation patterns and responses to sensory stimuli, have been understudied. However, recent work demonstrates that epidermal signals dictate patterns of SSN skin innervation through a variety of mechanisms including targeting afferents to the epidermis, providing instructive cues for branching morphogenesis, growth control and structural stability of neurites, and facilitating neurite-neurite interactions. Here, we focus onstudies conducted in worms (Caenorhabditis elegans), fruit flies (Drosophila melanogaster), and zebrafish (Danio rerio): prominent model systems in which anatomical and genetic analyses have defined fundamental principles by which epidermal cells govern SSN development.
Collapse
Affiliation(s)
| | | | | | - Jay Z. Parrish
- Department of Biology, University of Washington, Seattle, WA, United States
| |
Collapse
|
41
|
Nazareth L, St John J, Murtaza M, Ekberg J. Phagocytosis by Peripheral Glia: Importance for Nervous System Functions and Implications in Injury and Disease. Front Cell Dev Biol 2021; 9:660259. [PMID: 33898462 PMCID: PMC8060502 DOI: 10.3389/fcell.2021.660259] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
The central nervous system (CNS) has very limited capacity to regenerate after traumatic injury or disease. In contrast, the peripheral nervous system (PNS) has far greater capacity for regeneration. This difference can be partly attributed to variances in glial-mediated functions, such as axon guidance, structural support, secretion of growth factors and phagocytic activity. Due to their growth-promoting characteristic, transplantation of PNS glia has been trialed for neural repair. After peripheral nerve injuries, Schwann cells (SCs, the main PNS glia) phagocytose myelin debris and attract macrophages to the injury site to aid in debris clearance. One peripheral nerve, the olfactory nerve, is unique in that it continuously regenerates throughout life. The olfactory nerve glia, olfactory ensheathing cells (OECs), are the primary phagocytes within this nerve, continuously clearing axonal debris arising from the normal regeneration of the nerve and after injury. In contrast to SCs, OECs do not appear to attract macrophages. SCs and OECs also respond to and phagocytose bacteria, a function likely critical for tackling microbial invasion of the CNS via peripheral nerves. However, phagocytosis is not always effective; inflammation, aging and/or genetic factors may contribute to compromised phagocytic activity. Here, we highlight the diverse roles of SCs and OECs with the focus on their phagocytic activity under physiological and pathological conditions. We also explore why understanding the contribution of peripheral glia phagocytosis may provide us with translational strategies for achieving axonal regeneration of the injured nervous system and potentially for the treatment of certain neurological diseases.
Collapse
Affiliation(s)
- Lynn Nazareth
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia
| | - James St John
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Mariyam Murtaza
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Jenny Ekberg
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| |
Collapse
|
42
|
Fujita Y, Yamashita T. Mechanisms and significance of microglia-axon interactions in physiological and pathophysiological conditions. Cell Mol Life Sci 2021; 78:3907-3919. [PMID: 33507328 PMCID: PMC11072252 DOI: 10.1007/s00018-021-03758-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/28/2020] [Accepted: 01/06/2021] [Indexed: 12/15/2022]
Abstract
Microglia are the resident immune cells of the central nervous system, and are important for cellular processes. In addition to their classical roles in pathophysiological conditions, these immune cells also dynamically interact with neurons and influence their structure and function in physiological conditions. Microglia have been shown to contact neurons at various points, including the dendrites, cell bodies, synapses, and axons, and support various developmental functions, such as neuronal survival, axon elongation, and maturation of the synaptic circuit. This review summarizes the current knowledge regarding the roles of microglia in brain development, with particular emphasis on microglia-axon interactions. We will review recent findings regarding the functions and signaling pathways involved in the reciprocal interactions between microglia and neurons. Moreover, as these interactions are altered in disease and injury conditions, we also discuss the effect and alteration of microglia-axon interactions in disease progression and the potential role of microglia in developmental brain disorders.
Collapse
Affiliation(s)
- Yuki Fujita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- WPI Immunology Frontier Research Center, Osaka University, 3-1, Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- WPI Immunology Frontier Research Center, Osaka University, 3-1, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Graduate School of Frontier Bioscience, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
| |
Collapse
|
43
|
Axonal chemokine-like Orion induces astrocyte infiltration and engulfment during mushroom body neuronal remodeling. Nat Commun 2021; 12:1849. [PMID: 33758182 PMCID: PMC7988174 DOI: 10.1038/s41467-021-22054-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 02/25/2021] [Indexed: 11/13/2022] Open
Abstract
The remodeling of neurons is a conserved fundamental mechanism underlying nervous system maturation and function. Astrocytes can clear neuronal debris and they have an active role in neuronal remodeling. Developmental axon pruning of Drosophila memory center neurons occurs via a degenerative process mediated by infiltrating astrocytes. However, how astrocytes are recruited to the axons during brain development is unclear. Using an unbiased screen, we identify the gene requirement of orion, encoding for a chemokine-like protein, in the developing mushroom bodies. Functional analysis shows that Orion is necessary for both axonal pruning and removal of axonal debris. Orion performs its functions extracellularly and bears some features common to chemokines, a family of chemoattractant cytokines. We propose that Orion is a neuronal signal that elicits astrocyte infiltration and astrocyte-driven axonal engulfment required during neuronal remodeling in the Drosophila developing brain. Astrocytes can engulf axonal debris in the developing brain. However, the mechanisms regulating astrocyte recruitment to the proper axons is unclear. Here, the authors identify Orion as a signal for astrocyte infiltration and engulfment to the mushroom bodies in the Drosophila developing brain.
Collapse
|
44
|
Vita DJ, Meier CJ, Broadie K. Neuronal fragile X mental retardation protein activates glial insulin receptor mediated PDF-Tri neuron developmental clearance. Nat Commun 2021; 12:1160. [PMID: 33608547 PMCID: PMC7896095 DOI: 10.1038/s41467-021-21429-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 01/08/2021] [Indexed: 01/31/2023] Open
Abstract
Glia engulf and phagocytose neurons during neural circuit developmental remodeling. Disrupting this pruning process contributes to Fragile X syndrome (FXS), a leading cause of intellectual disability and autism spectrum disorder in mammals. Utilizing a Drosophila FXS model central brain circuit, we identify two glial classes responsible for Draper-dependent elimination of developmentally transient PDF-Tri neurons. We find that neuronal Fragile X Mental Retardation Protein (FMRP) drives insulin receptor activation in glia, promotes glial Draper engulfment receptor expression, and negatively regulates membrane-molding ESCRT-III Shrub function during PDF-Tri neuron clearance during neurodevelopment in Drosophila. In this context, we demonstrate genetic interactions between FMRP and insulin receptor signaling, FMRP and Draper, and FMRP and Shrub in PDF-Tri neuron elimination. We show that FMRP is required within neurons, not glia, for glial engulfment, indicating FMRP-dependent neuron-to-glia signaling mediates neuronal clearance. We conclude neuronal FMRP drives glial insulin receptor activation to facilitate Draper- and Shrub-dependent neuronal clearance during neurodevelopment in Drosophila.
Collapse
Affiliation(s)
- Dominic J Vita
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Cole J Meier
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
- Kennedy Center for Research on Human Development, Nashville, TN, USA.
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, USA.
| |
Collapse
|
45
|
Hsu JM, Kang Y, Corty MM, Mathieson D, Peters OM, Freeman MR. Injury-Induced Inhibition of Bystander Neurons Requires dSarm and Signaling from Glia. Neuron 2021; 109:473-487.e5. [PMID: 33296670 PMCID: PMC7864878 DOI: 10.1016/j.neuron.2020.11.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 09/28/2020] [Accepted: 11/13/2020] [Indexed: 12/12/2022]
Abstract
Nervous system injury and disease have broad effects on the functional connectivity of the nervous system, but how injury signals are spread across neural circuits remains unclear. We explored how axotomy changes the physiology of severed axons and adjacent uninjured "bystander" neurons in a simple in vivo nerve preparation. Within hours after injury, we observed suppression of axon transport in all axons, whether injured or not, and decreased mechano- and chemosensory signal transduction in uninjured bystander neurons. Unexpectedly, we found the axon death molecule dSarm, but not its NAD+ hydrolase activity, was required cell autonomously for these early changes in neuronal cell biology in bystander neurons, as were the voltage-gated calcium channel Cacophony (Cac) and the mitogen-activated protein kinase (MAPK) signaling cascade. Bystander neurons functionally recovered at later time points, while severed axons degenerated via α/Armadillo/Toll-interleukin receptor homology domain (dSarm)/Axundead signaling, and independently of Cac/MAPK. Interestingly, suppression of bystander neuron function required Draper/MEGF10 signaling in glia, indicating glial cells spread injury signals and actively suppress bystander neuron function. Our work identifies a new role for dSarm and glia in suppression of bystander neuron function after injury and defines two genetically and temporally separable phases of dSarm signaling in the injured nervous system.
Collapse
Affiliation(s)
- Jiun-Min Hsu
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Yunsik Kang
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Megan M Corty
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Danielle Mathieson
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Owen M Peters
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Marc R Freeman
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA.
| |
Collapse
|
46
|
Nagai J, Yu X, Papouin T, Cheong E, Freeman MR, Monk KR, Hastings MH, Haydon PG, Rowitch D, Shaham S, Khakh BS. Behaviorally consequential astrocytic regulation of neural circuits. Neuron 2020; 109:576-596. [PMID: 33385325 DOI: 10.1016/j.neuron.2020.12.008] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/23/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022]
Abstract
Astrocytes are a large and diverse population of morphologically complex cells that exist throughout nervous systems of multiple species. Progress over the last two decades has shown that astrocytes mediate developmental, physiological, and pathological processes. However, a long-standing open question is how astrocytes regulate neural circuits in ways that are behaviorally consequential. In this regard, we summarize recent studies using Caenorhabditis elegans, Drosophila melanogaster, Danio rerio, and Mus musculus. The data reveal diverse astrocyte mechanisms operating in seconds or much longer timescales within neural circuits and shaping multiple behavioral outputs. We also refer to human diseases that have a known primary astrocytic basis. We suggest that including astrocytes in mechanistic, theoretical, and computational studies of neural circuits provides new perspectives to understand behavior, its regulation, and its disease-related manifestations.
Collapse
Affiliation(s)
- Jun Nagai
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; RIKEN Center for Brain Science, 2-1 Hirosawa Wako City, Saitama 351-0198, Japan
| | - Xinzhu Yu
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 514 Burrill Hall, 407 S. Goodwin Ave, Urbana, IL 61801, USA
| | - Thomas Papouin
- Department of Neuroscience, Washington University in St. Louis, School of Medicine, Campus Box 8108, 660 South Euclid Ave., St. Louis, MO 63110, USA
| | - Eunji Cheong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
| | - Marc R Freeman
- The Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Kelly R Monk
- The Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Michael H Hastings
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Philip G Haydon
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | - David Rowitch
- Department of Paediatrics, Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK; Departments of Pediatrics and Neurosurgery, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA.
| |
Collapse
|
47
|
Lago-Baldaia I, Fernandes VM, Ackerman SD. More Than Mortar: Glia as Architects of Nervous System Development and Disease. Front Cell Dev Biol 2020; 8:611269. [PMID: 33381506 PMCID: PMC7767919 DOI: 10.3389/fcell.2020.611269] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022] Open
Abstract
Glial cells are an essential component of the nervous system of vertebrates and invertebrates. In the human brain, glia are as numerous as neurons, yet the importance of glia to nearly every aspect of nervous system development has only been expounded over the last several decades. Glia are now known to regulate neural specification, synaptogenesis, synapse function, and even broad circuit function. Given their ubiquity, it is not surprising that the contribution of glia to neuronal disease pathogenesis is a growing area of research. In this review, we will summarize the accumulated evidence of glial participation in several distinct phases of nervous system development and organization-neural specification, circuit wiring, and circuit function. Finally, we will highlight how these early developmental roles of glia contribute to nervous system dysfunction in neurodevelopmental and neurodegenerative disorders.
Collapse
Affiliation(s)
- Inês Lago-Baldaia
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Vilaiwan M. Fernandes
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Sarah D. Ackerman
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, OR, United States
| |
Collapse
|
48
|
Furusawa K, Emoto K. Spatiotemporal regulation of developmental neurite pruning: Molecular and cellular insights from Drosophila models. Neurosci Res 2020; 167:54-63. [PMID: 33309868 DOI: 10.1016/j.neures.2020.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/10/2020] [Accepted: 11/10/2020] [Indexed: 02/02/2023]
Abstract
Developmental neurite pruning is a process by which neurons selectively eliminate unnecessary processes of axons and/or dendrites without cell death, which shapes the mature wiring of nervous systems. In this sense, developmental neurite pruning requires spatiotemporally precise control of local degradation of cellular components including cytoskeletons and membranes. The Drosophila nervous system undergoes large-scale remodeling, including axon/dendrite pruning, during metamorphosis. In addition to this unique phenomenon in the nervous system, powerful genetic tools make the Drosophila nervous system a sophisticated model to investigate spatiotemporal regulation of neural remodeling. This article reviews recent advances to our understanding of the molecular and cellular mechanisms of developmental axon/dendrite pruning, mainly focusing on studies in Drosophila sensory neurons and mushroom body neurons.
Collapse
Affiliation(s)
- Kotaro Furusawa
- Department of Biological Sciences, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kazuo Emoto
- Department of Biological Sciences, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| |
Collapse
|
49
|
Arai K. [Pharmaceutical Research and Education]. YAKUGAKU ZASSHI 2020; 140:1107-1117. [PMID: 32879243 DOI: 10.1248/yakushi.20-00123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The true central aim of pharmaceutical research and education is to strive for the patient's satisfaction, i.e., "for the sake of the patient". Our research focuses to bridge the gap between the ideal and current situation in pharmaceutical science. We also investigated/questioned the united roles of pharmacists and pharmacies, with the ambition of changing the work culture of pharmacists. This paper reviews the history of our research and discusses the future of pharmaceutical research and education.
Collapse
Affiliation(s)
- Kunizo Arai
- Faculty of Pharmacy, Institute of Medical, Pharmaceutical, and Health Sciences, Kanazawa University
| |
Collapse
|
50
|
Cherra SJ, Goncharov A, Boassa D, Ellisman M, Jin Y. C. elegans MAGU-2/Mpp5 homolog regulates epidermal phagocytosis and synapse density. J Neurogenet 2020; 34:298-306. [PMID: 32366143 DOI: 10.1080/01677063.2020.1726915] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Synapses are dynamic connections that underlie essential functions of the nervous system. The addition, removal, and maintenance of synapses govern the flow of information in neural circuits throughout the lifetime of an animal. While extensive studies have elucidated many intrinsic mechanisms that neurons employ to modulate their connections, increasing evidence supports the roles of non-neuronal cells, such as glia, in synapse maintenance and circuit function. We previously showed that C. elegans epidermis regulates synapses through ZIG-10, a cell-adhesion protein of the immunoglobulin domain superfamily. Here we identified a member of the Pals1/MPP5 family, MAGU-2, that functions in the epidermis to modulate phagocytosis and the number of synapses by regulating ZIG-10 localization. Furthermore, we used light and electron microscopy to show that this epidermal mechanism removes neuronal membranes from the neuromuscular junction, dependent on the conserved phagocytic receptor CED-1. Together, our study shows that C. elegans epidermis constrains synaptic connectivity, in a manner similar to astrocytes and microglia in mammals, allowing optimized output of neural circuits.
Collapse
Affiliation(s)
- Salvatore J Cherra
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.,Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Alexandr Goncharov
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Daniela Boassa
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, CA, USA
| | - Mark Ellisman
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, CA, USA.,Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.,Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA
| |
Collapse
|