1
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Schmitd LB, Hafner H, Ward A, Asghari Adib E, Biscola NP, Kohen R, Patel M, Williamson RE, Desai E, Bennett J, Saxman G, Athaiya M, Wilborn D, Shumpert J, Zhao XF, Kawaguchi R, Geschwind DH, Hoke A, Shrager P, Collins CA, Havton LA, Kalinski AL, Giger RJ. Sarm1 is not necessary for activation of neuron-intrinsic growth programs yet required for the Schwann cell repair response and peripheral nerve regeneration. bioRxiv 2024:2024.03.04.583374. [PMID: 38496662 PMCID: PMC10942360 DOI: 10.1101/2024.03.04.583374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Upon peripheral nervous system (PNS) injury, severed axons undergo rapid SARM1-dependent Wallerian degeneration (WD). In mammals, the role of SARM1 in PNS regeneration, however, is unknown. Here we demonstrate that Sarm1 is not required for axotomy induced activation of neuron-intrinsic growth programs and axonal growth into a nerve crush site. However, in the distal nerve, Sarm1 is necessary for the timely induction of the Schwann cell (SC) repair response, nerve inflammation, myelin clearance, and regeneration of sensory and motor axons. In Sarm1-/- mice, regenerated fibers exhibit reduced axon caliber, defective nerve conduction, and recovery of motor function is delayed. The growth hostile environment of Sarm1-/- distal nerve tissue was demonstrated by grafting of Sarm1-/- nerve into WT recipients. SC lineage tracing in injured WT and Sarm1-/- mice revealed morphological differences. In the Sarm1-/- distal nerve, the appearance of p75NTR+, c-Jun+ SCs is significantly delayed. Ex vivo, p75NTR and c-Jun upregulation in Sarm1-/- nerves can be rescued by pharmacological inhibition of ErbB kinase. Together, our studies show that Sarm1 is not necessary for the activation of neuron intrinsic growth programs but in the distal nerve is required for the orchestration of cellular programs that underlie rapid axon extension.
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Affiliation(s)
- Ligia B. Schmitd
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Hannah Hafner
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Ayobami Ward
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Neurosurgery, University of Michigan Medical School, Ann Arbor MI, USA
| | - Elham Asghari Adib
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Natalia P. Biscola
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Rafi Kohen
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Manav Patel
- Department of Biology, Ball State University, Muncie IN, USA
| | | | - Emily Desai
- Department of Biology, Ball State University, Muncie IN, USA
| | | | - Grace Saxman
- Department of Biology, Ball State University, Muncie IN, USA
| | - Mitre Athaiya
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - David Wilborn
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Jaisha Shumpert
- Department of Biology, Ball State University, Muncie IN, USA
| | - Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Riki Kawaguchi
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Daniel H. Geschwind
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
- Institute of Precision Health, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ahmet Hoke
- Department of Neurology, The Johns Hopkins University, Baltimore, MD, USA
| | - Peter Shrager
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
| | - Catherine A. Collins
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Leif A. Havton
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- James J Peters VA Medical Center, Bronx, NY, USA
| | - Ashley L. Kalinski
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Biology, Ball State University, Muncie IN, USA
| | - Roman J. Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor MI, USA
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2
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Nagy GN, Zhao XF, Karlsson R, Wang K, Duman R, Harlos K, El Omari K, Wagner A, Clausen H, Miller RL, Giger RJ, Jones EY. Structure and function of Semaphorin-5A glycosaminoglycan interactions. Nat Commun 2024; 15:2723. [PMID: 38548715 PMCID: PMC10978931 DOI: 10.1038/s41467-024-46725-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 03/07/2024] [Indexed: 04/01/2024] Open
Abstract
Integration of extracellular signals by neurons is pivotal for brain development, plasticity, and repair. Axon guidance relies on receptor-ligand interactions crosstalking with extracellular matrix components. Semaphorin-5A (Sema5A) is a bifunctional guidance cue exerting attractive and inhibitory effects on neuronal growth through the interaction with heparan sulfate (HS) and chondroitin sulfate (CS) glycosaminoglycans (GAGs), respectively. Sema5A harbors seven thrombospondin type-1 repeats (TSR1-7) important for GAG binding, however the underlying molecular basis and functions in vivo remain enigmatic. Here we dissect the structural basis for Sema5A:GAG specificity and demonstrate the functional significance of this interaction in vivo. Using x-ray crystallography, we reveal a dimeric fold variation for TSR4 that accommodates GAG interactions. TSR4 co-crystal structures identify binding residues validated by site-directed mutagenesis. In vitro and cell-based assays uncover specific GAG epitopes necessary for TSR association. We demonstrate that HS-GAG binding is preferred over CS-GAG and mediates Sema5A oligomerization. In vivo, Sema5A:GAG interactions are necessary for Sema5A function and regulate Plexin-A2 dependent dentate progenitor cell migration. Our study rationalizes Sema5A associated developmental and neurological disorders and provides mechanistic insights into how multifaceted guidance functions of a single transmembrane cue are regulated by proteoglycans.
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Affiliation(s)
- Gergely N Nagy
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Budapest, Hungary.
- Institute of Molecular Life Sciences, HUN-REN Research Centre for Natural Sciences, Budapest, Hungary.
| | - Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Richard Karlsson
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen-N, Denmark
| | - Karen Wang
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ramona Duman
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Karl Harlos
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Kamel El Omari
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Armin Wagner
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Henrik Clausen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen-N, Denmark
| | - Rebecca L Miller
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen-N, Denmark.
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.
- Department of Neurology, Ann Arbor, MI, USA.
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
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3
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Passino R, Finneran MC, Hafner H, Feng Q, Huffman LD, Zhao XF, Johnson CN, Kawaguchi R, Oses-Prieto JA, Burlingame AL, Geschwind DH, Benowitz LI, Giger RJ. Neutrophil-inflicted vasculature damage suppresses immune-mediated optic nerve regeneration. Cell Rep 2024; 43:113931. [PMID: 38492223 DOI: 10.1016/j.celrep.2024.113931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 01/03/2024] [Accepted: 02/21/2024] [Indexed: 03/18/2024] Open
Abstract
In adult mammals, injured retinal ganglion cells (RGCs) fail to spontaneously regrow severed axons, resulting in permanent visual deficits. Robust axon growth, however, is observed after intra-ocular injection of particulate β-glucan isolated from yeast. Blood-borne myeloid cells rapidly respond to β-glucan, releasing numerous pro-regenerative factors. Unfortunately, the pro-regenerative effects are undermined by retinal damage inflicted by an overactive immune system. Here, we demonstrate that protection of the inflamed vasculature promotes immune-mediated RGC regeneration. In the absence of microglia, leakiness of the blood-retina barrier increases, pro-inflammatory neutrophils are elevated, and RGC regeneration is reduced. Functional ablation of the complement receptor 3 (CD11b/integrin-αM), but not the complement components C1q-/- or C3-/-, reduces ocular inflammation, protects the blood-retina barrier, and enhances RGC regeneration. Selective targeting of neutrophils with anti-Ly6G does not increase axogenic neutrophils but protects the blood-retina barrier and enhances RGC regeneration. Together, these findings reveal that protection of the inflamed vasculature promotes neuronal regeneration.
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Affiliation(s)
- Ryan Passino
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Matthew C Finneran
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Hannah Hafner
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Qian Feng
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Lucas D Huffman
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Craig N Johnson
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Riki Kawaguchi
- Departments of Psychiatry and Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Juan A Oses-Prieto
- University of California San Francisco, Department of Pharmaceutical Chemistry, San Francisco, CA 94158, USA
| | - Alma L Burlingame
- University of California San Francisco, Department of Pharmaceutical Chemistry, San Francisco, CA 94158, USA
| | - Daniel H Geschwind
- Departments of Psychiatry and Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Program in Neurogenetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute of Precision Health, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Larry I Benowitz
- Departments of Neurosurgery and Ophthalmology, Harvard Medical School, Boston, MA 02115, USA; Department of Neurosurgery, Boston Children's Hospital, Boston MA 02115, USA; Departmant of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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4
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Asghari Adib E, Shadrach JL, Reilly-Jankowiak L, Dwivedi MK, Rogers AE, Shahzad S, Passino R, Giger RJ, Pierchala BA, Collins CA. DLK signaling in axotomized neurons triggers complement activation and loss of upstream synapses. Cell Rep 2024; 43:113801. [PMID: 38363678 DOI: 10.1016/j.celrep.2024.113801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/27/2023] [Accepted: 01/31/2024] [Indexed: 02/18/2024] Open
Abstract
Axotomized spinal motoneurons (MNs) lose presynaptic inputs following peripheral nerve injury; however, the cellular mechanisms that lead to this form of synapse loss are currently unknown. Here, we delineate a critical role for neuronal kinase dual leucine zipper kinase (DLK)/MAP3K12, which becomes activated in axotomized neurons. Studies with conditional knockout mice indicate that DLK signaling activation in injured MNs triggers the induction of phagocytic microglia and synapse loss. Aspects of the DLK-regulated response include expression of C1q first from the axotomized MN and then later in surrounding microglia, which subsequently phagocytose presynaptic components of upstream synapses. Pharmacological ablation of microglia inhibits the loss of cholinergic C boutons from axotomized MNs. Together, the observations implicate a neuronal mechanism, governed by the DLK, in the induction of inflammation and the removal of synapses.
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Affiliation(s)
- Elham Asghari Adib
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Jennifer L Shadrach
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, USA
| | | | - Manish K Dwivedi
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Abigail E Rogers
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Shameena Shahzad
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Ryan Passino
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Brian A Pierchala
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, USA; Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Catherine A Collins
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA.
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5
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Pinskey JM, Hoard TM, Zhao XF, Franks NE, Frank ZC, McMellen AN, Giger RJ, Allen BL. Plexins promote hedgehog signaling through their cytoplasmic GAP activity. eLife 2022; 11:74750. [PMID: 36169302 PMCID: PMC9553217 DOI: 10.7554/elife.74750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 09/27/2022] [Indexed: 11/22/2022] Open
Abstract
Hedgehog signaling controls tissue patterning during embryonic and postnatal development and continues to play important roles throughout life. Characterizing the full complement of Hedgehog pathway components is essential to understanding its wide-ranging functions. Previous work has identified neuropilins, established semaphorin receptors, as positive regulators of Hedgehog signaling. Neuropilins require plexin co-receptors to mediate semaphorin signaling, but the role of plexins in Hedgehog signaling has not yet been explored. Here, we provide evidence that multiple plexins promote Hedgehog signaling in NIH/3T3 mouse fibroblasts and that plexin loss of function in these cells results in significantly reduced Hedgehog pathway activity. Catalytic activity of the plexin GTPase-activating protein (GAP) domain is required for Hedgehog signal promotion, and constitutive activation of the GAP domain further amplifies Hedgehog signaling. Additionally, we demonstrate that plexins promote Hedgehog signaling at the level of GLI transcription factors and that this promotion requires intact primary cilia. Finally, we find that plexin loss of function significantly reduces the response to Hedgehog pathway activation in the mouse dentate gyrus. Together, these data identify plexins as novel components of the Hedgehog pathway and provide insight into their mechanism of action.
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Affiliation(s)
- Justine M Pinskey
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, United States
| | - Tyler M Hoard
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, United States
| | - Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, United States
| | - Nicole E Franks
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, United States
| | - Zoë C Frank
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, United States
| | - Alexandra N McMellen
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, United States
| | - Benjamin L Allen
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor, Ann Arbor, United States
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6
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Yang T, Veling MW, Zhao XF, Prin NP, Zhu L, Hergenreder T, Liu H, Liu L, Rane ZS, Savelieff MG, Fuerst PG, Li Q, Kwan KY, Giger RJ, Wang Y, Ye B. Migrating Pyramidal Neurons Require DSCAM to Bypass the Border of the Developing Cortical Plate. J Neurosci 2022; 42:5510-5521. [PMID: 35672151 PMCID: PMC9295838 DOI: 10.1523/jneurosci.0997-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 01/16/2023] Open
Abstract
During mammalian neocortex development, nascent pyramidal neurons migrate along radial glial cells and overtake earlier-born neurons to terminate at the front of the developing cortical plate (CP), leading to the outward expansion of the CP border. While much has been learned about the cellular and molecular mechanisms that underlie the migration of pyramidal neurons, how migrating neurons bypass the preceding neurons at the end of migration to reach their final positions remains poorly understood. Here, we report that Down syndrome cell adhesion molecule (DSCAM) is required for migrating neurons to bypass their postmigratory predecessors during the expansion of the upper cortical layers. DSCAM is a type I transmembrane cell adhesion molecule. It has been linked to Down syndrome through its location on Chromosome 21 trisomy and to autism spectrum disorders through loss-of-function mutations. Ex vivo time-lapse imaging demonstrates that DSCAM is required for migrating neurons to bypass their postmigratory predecessors, crossing the CP border to expand the upper cortical layers. In DSCAM-deficient cortices, migrating neurons stop prematurely under the CP border, leading to thinner upper cortical layers with higher neuronal density. We further show that DSCAM weakens cell adhesion mediated by N-cadherin in the upper cortical plate, allowing migrating neurons to traverse the CP border and expand the CP. These findings suggest that DSCAM is required for proper migratory termination and final positioning of nascent pyramidal neurons, which may provide insight into brain disorders that exhibit thinner upper layers of the cerebral cortex without neuronal loss.SIGNIFICANCE STATEMENT Newly born neurons in the developing mammalian neocortex migrate outward toward the cortical surface, bypassing earlier born neurons to expand the developing cortex. How migrating neurons bypass the preceding neurons and terminate at the front of the expanding cortex remains poorly understood. We demonstrate that Down syndrome cell adhesion molecule (DSCAM), linked to Down syndrome and autism spectrum disorder, is required by migrating neurons to bypass their postmigratory predecessors and terminate migration in the outwardly expanding cortical layer. Migrating neurons deficient in DSCAM stop prematurely, failing to expand the cortex. We further show that DSCAM likely mediates migratory termination by weakening cell adhesion mediated by N-cadherin.
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Affiliation(s)
- Tao Yang
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Macy W Veling
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Nicholas P Prin
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Limei Zhu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Ty Hergenreder
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Hao Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Lu Liu
- Internal Medicine, Hematology/Oncology, University of Michigan, Ann Arbor, Michigan 48109
| | - Zachary S Rane
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Masha G Savelieff
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Peter G Fuerst
- Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844
| | - Qing Li
- Internal Medicine, Hematology/Oncology, University of Michigan, Ann Arbor, Michigan 48109
| | - Kenneth Y Kwan
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan 48109
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Yu Wang
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Bing Ye
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
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7
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Benowitz LI, Dowling JE, Giger RJ, Johnson TV, Zack DJ. Restoring partial vision to a blind patient. Fac Rev 2022; 11:17. [PMID: 35812361 PMCID: PMC9239363 DOI: 10.12703/r-01-0000012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
This paper reports an important breakthrough in partially restoring sight to a man who had lost his vision due to retinitis pigmentosa (RP), a heritable retinal degenerative disease that affects approximately 1 in 4000 people. Long considered an insurmountable challenge, a stellar team of vision scientists, engineers, basic biologists, and others, working together for many years, has enabled a man who had been legally blind for decades to begin distinguishing objects and navigating his environment1.
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Affiliation(s)
| | | | | | - Thomas V Johnson
- Wilmer Eye Institute, Johns Hopkins University School of Medicine
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8
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Zhao XF, Huffman LD, Hafner H, Athaiya M, Finneran MC, Kalinski AL, Kohen R, Flynn C, Passino R, Johnson CN, Kohrman D, Kawaguchi R, Yang LJS, Twiss JL, Geschwind DH, Corfas G, Giger RJ. The injured sciatic nerve atlas (iSNAT), insights into the cellular and molecular basis of neural tissue degeneration and regeneration. eLife 2022; 11:80881. [PMID: 36515985 PMCID: PMC9829412 DOI: 10.7554/elife.80881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 11/30/2022] [Indexed: 12/15/2022] Open
Abstract
Upon trauma, the adult murine peripheral nervous system (PNS) displays a remarkable degree of spontaneous anatomical and functional regeneration. To explore extrinsic mechanisms of neural repair, we carried out single-cell analysis of naïve mouse sciatic nerve, peripheral blood mononuclear cells, and crushed sciatic nerves at 1 day, 3 days, and 7 days following injury. During the first week, monocytes and macrophages (Mo/Mac) rapidly accumulate in the injured nerve and undergo extensive metabolic reprogramming. Proinflammatory Mo/Mac with a high glycolytic flux dominate the early injury response and rapidly give way to inflammation resolving Mac, programmed toward oxidative phosphorylation. Nerve crush injury causes partial leakiness of the blood-nerve barrier, proliferation of endoneurial and perineurial stromal cells, and entry of opsonizing serum proteins. Micro-dissection of the nerve injury site and distal nerve, followed by single-cell RNA-sequencing, identified distinct immune compartments, triggered by mechanical nerve wounding and Wallerian degeneration, respectively. This finding was independently confirmed with Sarm1-/- mice, in which Wallerian degeneration is greatly delayed. Experiments with chimeric mice showed that wildtype immune cells readily enter the injury site in Sarm1-/- mice, but are sparse in the distal nerve, except for Mo. We used CellChat to explore intercellular communications in the naïve and injured PNS and report on hundreds of ligand-receptor interactions. Our longitudinal analysis represents a new resource for neural tissue regeneration, reveals location- specific immune microenvironments, and reports on large intercellular communication networks. To facilitate mining of scRNAseq datasets, we generated the injured sciatic nerve atlas (iSNAT): https://cdb-rshiny.med.umich.edu/Giger_iSNAT/.
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Affiliation(s)
- Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States
| | - Lucas D Huffman
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States,Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
| | - Hannah Hafner
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States
| | - Mitre Athaiya
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States,Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
| | - Matthew C Finneran
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States,Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
| | - Ashley L Kalinski
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States
| | - Rafi Kohen
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States,Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
| | - Corey Flynn
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States
| | - Ryan Passino
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States
| | - Craig N Johnson
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States
| | - David Kohrman
- Kresge Hearing Institute, University of Michigan–Ann ArborAnn ArborUnited States
| | - Riki Kawaguchi
- Departments of Psychiatry and Neurology, University of California, Los AngelesLos AngelesUnited States
| | - Lynda JS Yang
- Department of Neurosurgery, University of Michigan-Ann ArborAnn ArborUnited States
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South CarolinaColumbiaUnited States
| | - Daniel H Geschwind
- Department of Neurology, Program in Neurogenetics, David Geffen School of Medicine, University of California, Los AngelesLos AngelesUnited States,Department of Human Genetics,David Geffen School of Medicine, University of California, Los AngelesLos AngelesUnited States,Institute of Precision Health, University of California, Los AngelesLos AngelesUnited States
| | - Gabriel Corfas
- Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States,Kresge Hearing Institute, University of Michigan–Ann ArborAnn ArborUnited States,Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan-Ann ArborAnn ArborUnited States,Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States,Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
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9
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Abstract
Neuronal injury can cause mitochondrial damage, leading to reduced energy production, decreased Ca2+ storage capacity, and increased reactive oxygen species. A new study reveals a mechanism to trigger the axonal transport of previously anchored mitochondria and promote neuroprotection and axon regeneration by replacing damaged with functional mitochondria.
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Affiliation(s)
- Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC 20208, USA.
| | | | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC 20208, USA
| | - Irene Dalla Costa
- Department of Biological Sciences, University of South Carolina, Columbia, SC 20208, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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10
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Garay PM, Chen A, Tsukahara T, Rodríguez Díaz JC, Kohen R, Althaus JC, Wallner MA, Giger RJ, Jones KS, Sutton MA, Iwase S. RAI1 Regulates Activity-Dependent Nascent Transcription and Synaptic Scaling. Cell Rep 2021; 32:108002. [PMID: 32783930 PMCID: PMC7418709 DOI: 10.1016/j.celrep.2020.108002] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/17/2020] [Accepted: 07/15/2020] [Indexed: 12/15/2022] Open
Abstract
Long-lasting forms of synaptic plasticity such as synaptic scaling are critically dependent on transcription. Activity-dependent transcriptional dynamics in neurons, however, remain incompletely characterized because most previous efforts relied on measurement of steady-state mRNAs. Here, we use nascent RNA sequencing to profile transcriptional dynamics of primary neuron cultures undergoing network activity shifts. We find pervasive transcriptional changes, in which ∼45% of expressed genes respond to network activity shifts. We further link retinoic acid-induced 1 (RAI1), the Smith-Magenis syndrome gene, to the transcriptional program driven by reduced network activity. Remarkable agreement among nascent transcriptomes, dynamic chromatin occupancy of RAI1, and electrophysiological properties of Rai1-deficient neurons demonstrates the essential roles of RAI1 in suppressing synaptic upscaling in the naive network, while promoting upscaling triggered by activity silencing. These results highlight the utility of bona fide transcription profiling to discover mechanisms of activity-dependent chromatin remodeling that underlie normal and pathological synaptic plasticity. BrU-seq reveals nascent transcription during synaptic up- or downscaling Smith-Magenis syndrome protein RAI1 regulates upscaling-associated transcription RAI1 departs chromatin in response to network activity shifts RAI1 blocks upscaling in naive networks and promotes inactivity-induced upscaling
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Affiliation(s)
- Patricia M Garay
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Alex Chen
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Takao Tsukahara
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Rafi Kohen
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - J Christian Althaus
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Margarete A Wallner
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI 48109, USA
| | - Roman J Giger
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA; Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA; Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Kevin S Jones
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Michael A Sutton
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Shigeki Iwase
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA.
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11
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Kalinski AL, Yoon C, Huffman LD, Duncker PC, Kohen R, Passino R, Hafner H, Johnson C, Kawaguchi R, Carbajal KS, Jara JS, Hollis E, Geschwind DH, Segal BM, Giger RJ. Analysis of the immune response to sciatic nerve injury identifies efferocytosis as a key mechanism of nerve debridement. eLife 2020; 9:60223. [PMID: 33263277 PMCID: PMC7735761 DOI: 10.7554/elife.60223] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 12/01/2020] [Indexed: 12/12/2022] Open
Abstract
Sciatic nerve crush injury triggers sterile inflammation within the distal nerve and axotomized dorsal root ganglia (DRGs). Granulocytes and pro-inflammatory Ly6Chigh monocytes infiltrate the nerve first and rapidly give way to Ly6Cnegative inflammation-resolving macrophages. In axotomized DRGs, few hematogenous leukocytes are detected and resident macrophages acquire a ramified morphology. Single-cell RNA-sequencing of injured sciatic nerve identifies five macrophage subpopulations, repair Schwann cells, and mesenchymal precursor cells. Macrophages at the nerve crush site are molecularly distinct from macrophages associated with Wallerian degeneration. In the injured nerve, macrophages ‘eat’ apoptotic leukocytes, a process called efferocytosis, and thereby promote an anti-inflammatory milieu. Myeloid cells in the injured nerve, but not axotomized DRGs, strongly express receptors for the cytokine GM-CSF. In GM-CSF-deficient (Csf2-/-) mice, inflammation resolution is delayed and conditioning-lesion-induced regeneration of DRG neuron central axons is abolished. Thus, carefully orchestrated inflammation resolution in the nerve is required for conditioning-lesion-induced neurorepair.
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Affiliation(s)
- Ashley L Kalinski
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Choya Yoon
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Lucas D Huffman
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States.,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, United States
| | - Patrick C Duncker
- Department of Neurology, University of Michigan Medical School, Ann Arbor, United States
| | - Rafi Kohen
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States.,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, United States
| | - Ryan Passino
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Hannah Hafner
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Craig Johnson
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Riki Kawaguchi
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Kevin S Carbajal
- Department of Neurology, University of Michigan Medical School, Ann Arbor, United States
| | | | - Edmund Hollis
- Burke Neurological Institute, White Plains, United States.,The Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, United States
| | - Daniel H Geschwind
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Benjamin M Segal
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, United States.,The Neurological Institute, The Ohio State University, Columbus, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States.,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, United States.,Department of Neurology, University of Michigan Medical School, Ann Arbor, United States
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12
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Sas AR, Carbajal KS, Jerome AD, Menon R, Yoon C, Kalinski AL, Giger RJ, Segal BM. A new neutrophil subset promotes CNS neuron survival and axon regeneration. Nat Immunol 2020; 21:1496-1505. [PMID: 33106668 PMCID: PMC7677206 DOI: 10.1038/s41590-020-00813-0] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 09/16/2020] [Indexed: 12/25/2022]
Abstract
Transected axons typically fail to regenerate in the central nervous system (CNS), resulting in chronic neurological disability in individuals with traumatic brain or spinal cord injury, glaucoma and ischemic reperfusion injury of the eye. Although neuroinflammation is often depicted as detrimental, there is growing evidence that alternatively activated, reparative leukocyte subsets and their products can be deployed to improve neurological outcomes. In the current study we identify a unique granulocyte subset, with characteristics of an immature neutrophil, that had neuroprotective properties and drove CNS axon regeneration in vivo, in part via secretion of a cocktail of growth factors. This pro-regenerative neutrophil promoted repair in the optic nerve and spinal cord, demonstrating its relevance across CNS compartments and neuronal populations. Our findings could ultimately lead to the development of novel immunotherapies that reverse CNS damage and restore lost neurological function across a spectrum of diseases.
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Affiliation(s)
- Andrew R Sas
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,The Neuroscience Research Institute, The Ohio State University, Columbus, OH, USA.,Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Kevin S Carbajal
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Andrew D Jerome
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.,The Neuroscience Research Institute, The Ohio State University, Columbus, OH, USA
| | - Rajasree Menon
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Choya Yoon
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Ashley L Kalinski
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Benjamin M Segal
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA. .,The Neuroscience Research Institute, The Ohio State University, Columbus, OH, USA. .,Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
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13
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Lenk GM, Jafar-Nejad P, Hill SF, Huffman LD, Smolen CE, Wagnon JL, Petit H, Yu W, Ziobro J, Bhatia K, Parent J, Giger RJ, Rigo F, Meisler MH. Scn8a Antisense Oligonucleotide Is Protective in Mouse Models of SCN8A Encephalopathy and Dravet Syndrome. Ann Neurol 2020; 87:339-346. [PMID: 31943325 PMCID: PMC7064908 DOI: 10.1002/ana.25676] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 01/07/2020] [Accepted: 01/07/2020] [Indexed: 12/19/2022]
Abstract
Objective SCN8A encephalopathy is a developmental and epileptic encephalopathy (DEE) caused by de novo gain‐of‐function mutations of sodium channel Nav1.6 that result in neuronal hyperactivity. Affected individuals exhibit early onset drug‐resistant seizures, developmental delay, and cognitive impairment. This study was carried out to determine whether reducing the abundance of the Scn8a transcript with an antisense oligonucleotide (ASO) would delay seizure onset and prolong survival in a mouse model of SCN8A encephalopathy. Methods ASO treatment was tested in a conditional mouse model with Cre‐dependent expression of the pathogenic patient SCN8A mutation p.Arg1872Trp (R1872W). This model exhibits early onset of seizures, rapid progression, and 100% penetrance. An Scn1a+/− haploinsufficient mouse model of Dravet syndrome was also treated. ASO was administered by intracerebroventricular injection at postnatal day 2, followed in some cases by stereotactic injection at postnatal day 30. Results We observed a dose‐dependent increase in length of survival from 15 to 65 days in the Scn8a‐R1872W/+ mice treated with ASO. Electroencephalographic recordings were normal prior to seizure onset. Weight gain and activity in an open field were unaffected, but treated mice were less active in a wheel running assay. A single treatment with Scn8a ASO extended survival of Dravet syndrome mice from 3 weeks to >5 months. Interpretation Reduction of Scn8a transcript by 25 to 50% delayed seizure onset and lethality in mouse models of SCN8A encephalopathy and Dravet syndrome. Reduction of SCN8A transcript is a promising approach to treatment of intractable childhood epilepsies. Ann Neurol 2020;87:339–346
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Affiliation(s)
- Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | | | - Sophie F Hill
- Department of Human Genetics, University of Michigan, Ann Arbor, MI.,Neuroscience Program, Ann Arbor, MI
| | - Lucas D Huffman
- Neuroscience Program, Ann Arbor, MI.,Department of Cell and Developmental Biology, Ann Arbor, MI
| | - Corrine E Smolen
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Jacy L Wagnon
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Hayley Petit
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Wenxi Yu
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Julie Ziobro
- Department of Neurology, University of Michigan, Ann Arbor, MI
| | - Kritika Bhatia
- Department of Neurology, University of Michigan, Ann Arbor, MI
| | - Jack Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI
| | - Roman J Giger
- Neuroscience Program, Ann Arbor, MI.,Department of Cell and Developmental Biology, Ann Arbor, MI.,Department of Neurology, University of Michigan, Ann Arbor, MI
| | | | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI.,Neuroscience Program, Ann Arbor, MI.,Department of Neurology, University of Michigan, Ann Arbor, MI
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14
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Zhao XF, Kohen R, Parent R, Duan Y, Fisher GL, Korn MJ, Ji L, Wan G, Jin J, Püschel AW, Dolan DF, Parent JM, Corfas G, Murphy GG, Giger RJ. PlexinA2 Forward Signaling through Rap1 GTPases Regulates Dentate Gyrus Development and Schizophrenia-like Behaviors. Cell Rep 2019; 22:456-470. [PMID: 29320740 PMCID: PMC5788190 DOI: 10.1016/j.celrep.2017.12.044] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/30/2017] [Accepted: 12/12/2017] [Indexed: 01/20/2023] Open
Abstract
Dentate gyrus (DG) development requires specification of granule cell (GC) progenitors in the hippocampal neuroepithelium, as well as their proliferation and migration into the primordial DG. We identify the Plexin family members Plxna2 and Plxna4 as important regulators of DG development. Distribution of immature GCs is regulated by Sema5A signaling through PlxnA2 and requires a functional PlxnA2 GTPase-activating protein (GAP) domain and Rap1 small GTPases. In adult Plxna2−/− but not Plxna2-GAP-deficient mice, the dentate GC layer is severely malformed, neurogenesis is compromised, and mossy fibers form aberrant synaptic boutons within CA3. Behavioral studies with Plxna2−/− mice revealed deficits in associative learning, sociability, and sensorimotor gating—traits commonly observed in neuropsychiatric disorder. Remarkably, while morphological defects are minimal in Plxna2-GAP-deficient brains, defects in fear memory and sensorimotor gating persist. Since allelic variants of human PLXNA2 and RAP1 associate with schizophrenia, our studies identify a biochemical pathway important for brain development and mental health.
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Affiliation(s)
- Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rafi Kohen
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rachel Parent
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuntao Duan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Grace L Fisher
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Matthew J Korn
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lingchao Ji
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Guoqiang Wan
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jing Jin
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence, University of Münster, 48149 Münster, Germany
| | - Andreas W Püschel
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence, University of Münster, 48149 Münster, Germany
| | - David F Dolan
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jack M Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gabriel Corfas
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Geoffrey G Murphy
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.
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15
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Pawelec KM, Yoon C, Giger RJ, Sakamoto J. Engineering a platform for nerve regeneration with direct application to nerve repair technology. Biomaterials 2019; 216:119263. [PMID: 31220794 DOI: 10.1016/j.biomaterials.2019.119263] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 06/05/2019] [Accepted: 06/07/2019] [Indexed: 12/16/2022]
Abstract
The development of effective treatment options for repair of peripheral nerves is complicated by lack of knowledge concerning the interactions between cells and implants. A promising device, the multichannel scaffold, incorporates microporous channels, aligning glia and directing axonal growth across a nerve gap. To enhance clinical outcomes of nerve repair, a platform, representative of current implant technology, was engineered which 1) recapitulated key device features (porosity and linearity) and 2) demonstrated remyelination of adult neurons. The in vitro platform began with the study of Schwann cells on porous polycaprolactone (PCL) and poly(lactide co-glycolide) (PLGA) substrates. Surface roughness determined glial cell attachment, and an additional layer of topography, 40 μm linear features, aligned Schwann cells and axons. In addition, direct co-culture of sensory neurons with Schwann cells significantly increased neurite outgrowth, compared to neurons cultured alone (naive or pre-conditioned). In contrast to the control substrate (glass), on porous PCL substrates, Schwann cells differentiated into a mature myelinating phenotype, expressing Oct-6, MPZ and MBP. The direct applicability of this platform to nerve implants, including its response to physiological cues, allows for optimization of cell-material interactions, close observation of the regeneration process, and the study of therapeutics, necessary to advance peripheral nerve repair technology.
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Affiliation(s)
- K M Pawelec
- University of Michigan, Department of Mechanical Engineering, Ann Arbor, MI, 48109, USA
| | - C Yoon
- University of Michigan, Department of Cell and Developmental Biology, Ann Arbor, MI, 48109, USA
| | - R J Giger
- University of Michigan, Department of Cell and Developmental Biology, Ann Arbor, MI, 48109, USA
| | - J Sakamoto
- University of Michigan, Department of Mechanical Engineering, Ann Arbor, MI, 48109, USA.
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16
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Kalinski AL, Kar AN, Craver J, Tosolini AP, Sleigh JN, Lee SJ, Hawthorne A, Brito-Vargas P, Miller-Randolph S, Passino R, Shi L, Wong VSC, Picci C, Smith DS, Willis DE, Havton LA, Schiavo G, Giger RJ, Langley B, Twiss JL. Deacetylation of Miro1 by HDAC6 blocks mitochondrial transport and mediates axon growth inhibition. J Cell Biol 2019; 218:1871-1890. [PMID: 31068376 PMCID: PMC6548128 DOI: 10.1083/jcb.201702187] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 02/15/2018] [Accepted: 04/15/2019] [Indexed: 02/08/2023] Open
Abstract
Inhibition of histone deacetylase 6 (HDAC6) was shown to support axon growth on the nonpermissive substrates myelin-associated glycoprotein (MAG) and chondroitin sulfate proteoglycans (CSPGs). Though HDAC6 deacetylates α-tubulin, we find that another HDAC6 substrate contributes to this axon growth failure. HDAC6 is known to impact transport of mitochondria, and we show that mitochondria accumulate in distal axons after HDAC6 inhibition. Miro and Milton proteins link mitochondria to motor proteins for axon transport. Exposing neurons to MAG and CSPGs decreases acetylation of Miro1 on Lysine 105 (K105) and decreases axonal mitochondrial transport. HDAC6 inhibition increases acetylated Miro1 in axons, and acetyl-mimetic Miro1 K105Q prevents CSPG-dependent decreases in mitochondrial transport and axon growth. MAG- and CSPG-dependent deacetylation of Miro1 requires RhoA/ROCK activation and downstream intracellular Ca2+ increase, and Miro1 K105Q prevents the decrease in axonal mitochondria seen with activated RhoA and elevated Ca2+ These data point to HDAC6-dependent deacetylation of Miro1 as a mediator of axon growth inhibition through decreased mitochondrial transport.
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Affiliation(s)
- Ashley L Kalinski
- Department of Biology, Drexel University, Philadelphia, PA.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | - John Craver
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | - Andrew P Tosolini
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - James N Sleigh
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | | | - Paul Brito-Vargas
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | | | - Ryan Passino
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Liang Shi
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | | | | | - Deanna S Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC
| | | | - Leif A Havton
- Departments of Neurology and Neurobiology, University of California, Los Angeles, Los Angeles, CA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute, University College London, London, UK.,Discoveries Centre for Regenerative and Precision Medicine, University College London Campus, London, UK
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
| | | | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC
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17
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Mironova YA, Lin JP, Kalinski AL, Huffman LD, Lenk GM, Havton LA, Meisler MH, Giger RJ. Protective role of the lipid phosphatase Fig4 in the adult nervous system. Hum Mol Genet 2019; 27:2443-2453. [PMID: 29688489 DOI: 10.1093/hmg/ddy145] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 04/16/2018] [Indexed: 12/11/2022] Open
Abstract
The signaling lipid phosphatidylinositol 3,5-bisphosphate, PI(3,5)P2, functions in vesicular trafficking through the endo-lysosomal compartment. Cellular levels of PI(3,5)P2 are regulated by an enzyme complex comprised of the kinase PIKFYVE, the phosphatase FIG4, and the scaffold protein VAC14. Mutations of human FIG4 cause inherited disorders including Charcot-Marie-Tooth disease type 4J, polymicrogyria with epilepsy, and Yunis-Varón syndrome. Constitutive Fig4-/- mice exhibit intention tremor, spongiform degeneration of neural tissue, hypomyelination, and juvenile lethality. To determine whether PI(3,5)P2 is required in the adult, we generated Fig4flox/-; CAG-creER mice and carried out tamoxifen-induced gene ablation. Global ablation in adulthood leads to wasting, tremor, and motor impairment. Death follows within 2 months of tamoxifen treatment, demonstrating a life-long requirement for Fig4. Histological examinations of the sciatic nerve revealed profound Wallerian degeneration of myelinated fibers, but not C-fiber axons in Remak bundles. In optic nerve sections, myelinated fibers appear morphologically intact and carry compound action potentials at normal velocity and amplitude. However, when iKO mice are challenged with a chemical white matter lesion, repair of damaged CNS myelin is significantly delayed, demonstrating a novel role for Fig4 in remyelination. Thus, in the adult PNS Fig4 is required to protect myelinated axons from Wallerian degeneration. In the adult CNS, Fig4 is dispensable for fiber stability and nerve conduction, but is required for the timely repair of damaged white matter. The greater vulnerability of the PNS to Fig4 deficiency in the mouse is consistent with clinical observations in patients with Charcot-Marie-Tooth disease.
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.,Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jing-Ping Lin
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ashley L Kalinski
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Lucas D Huffman
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.,Interdepartmental Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Leif A Havton
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Miriam H Meisler
- Interdepartmental Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.,Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA.,Interdepartmental Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, USA
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18
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Zhao XF, Kohen R, Parent R, Duan Y, Fisher GL, Korn MJ, Ji L, Wan G, Jin J, Püschel AW, Dolan DF, Parent JM, Corfas G, Murphy GG, Giger RJ. PlexinA2 Forward Signaling through Rap1 GTPases Regulates Dentate Gyrus Development and Schizophrenia-like Behaviors. Cell Rep 2018. [PMID: 29320740 DOI: 10.1016/j.celrep.2017.12.044.plexina2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023] Open
Abstract
Dentate gyrus (DG) development requires specification of granule cell (GC) progenitors in the hippocampal neuroepithelium, as well as their proliferation and migration into the primordial DG. We identify the Plexin family members Plxna2 and Plxna4 as important regulators of DG development. Distribution of immature GCs is regulated by Sema5A signaling through PlxnA2 and requires a functional PlxnA2 GTPase-activating protein (GAP) domain and Rap1 small GTPases. In adult Plxna2-/- but not Plxna2-GAP-deficient mice, the dentate GC layer is severely malformed, neurogenesis is compromised, and mossy fibers form aberrant synaptic boutons within CA3. Behavioral studies with Plxna2-/- mice revealed deficits in associative learning, sociability, and sensorimotor gating-traits commonly observed in neuropsychiatric disorder. Remarkably, while morphological defects are minimal in Plxna2-GAP-deficient brains, defects in fear memory and sensorimotor gating persist. Since allelic variants of human PLXNA2 and RAP1 associate with schizophrenia, our studies identify a biochemical pathway important for brain development and mental health.
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Affiliation(s)
- Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rafi Kohen
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rachel Parent
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuntao Duan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Grace L Fisher
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Matthew J Korn
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lingchao Ji
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Guoqiang Wan
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jing Jin
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence, University of Münster, 48149 Münster, Germany
| | - Andreas W Püschel
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität, 48149 Münster, Germany; Cells-in-Motion Cluster of Excellence, University of Münster, 48149 Münster, Germany
| | - David F Dolan
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jack M Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gabriel Corfas
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Geoffrey G Murphy
- Molecular & Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.
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19
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Lin JP, Mironova YA, Shrager P, Giger RJ. LRP1 regulates peroxisome biogenesis and cholesterol homeostasis in oligodendrocytes and is required for proper CNS myelin development and repair. eLife 2017; 6:30498. [PMID: 29251594 PMCID: PMC5752207 DOI: 10.7554/elife.30498] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 12/15/2017] [Indexed: 01/01/2023] Open
Abstract
Low-density lipoprotein receptor-related protein-1 (LRP1) is a large endocytic and signaling molecule broadly expressed by neurons and glia. In adult mice, global inducible (Lrp1flox/flox;CAG-CreER) or oligodendrocyte (OL)-lineage specific ablation (Lrp1flox/flox;Pdgfra-CreER) of Lrp1 attenuates repair of damaged white matter. In oligodendrocyte progenitor cells (OPCs), Lrp1 is required for cholesterol homeostasis and differentiation into mature OLs. Lrp1-deficient OPC/OLs show a strong increase in the sterol-regulatory element-binding protein-2 yet are unable to maintain normal cholesterol levels, suggesting more global metabolic deficits. Mechanistic studies revealed a decrease in peroxisomal biogenesis factor-2 and fewer peroxisomes in OL processes. Treatment of Lrp1−/− OPCs with cholesterol or activation of peroxisome proliferator-activated receptor-γ with pioglitazone alone is not sufficient to promote differentiation; however, when combined, cholesterol and pioglitazone enhance OPC differentiation into mature OLs. Collectively, our studies reveal a novel role for Lrp1 in peroxisome biogenesis, lipid homeostasis, and OPC differentiation during white matter development and repair.
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Affiliation(s)
- Jing-Ping Lin
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI, United States
| | - Yevgeniya A Mironova
- Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Peter Shrager
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI, United States.,Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, United States.,Interdepartmental Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, United States
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20
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Wehner AB, Abdesselem H, Dickendesher TL, Imai F, Yoshida Y, Giger RJ, Pierchala BA. Semaphorin 3A is a retrograde cell death signal in developing sympathetic neurons. Development 2017; 143:1560-70. [PMID: 27143756 DOI: 10.1242/dev.134627] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/29/2016] [Indexed: 12/30/2022]
Abstract
During development of the peripheral nervous system, excess neurons are generated, most of which will be lost by programmed cell death due to a limited supply of neurotrophic factors from their targets. Other environmental factors, such as 'competition factors' produced by neurons themselves, and axon guidance molecules have also been implicated in developmental cell death. Semaphorin 3A (Sema3A), in addition to its function as a chemorepulsive guidance cue, can also induce death of sensory neurons in vitro The extent to which Sema3A regulates developmental cell death in vivo, however, is debated. We show that in compartmentalized cultures of rat sympathetic neurons, a Sema3A-initiated apoptosis signal is retrogradely transported from axon terminals to cell bodies to induce cell death. Sema3A-mediated apoptosis utilizes the extrinsic pathway and requires both neuropilin 1 and plexin A3. Sema3A is not retrogradely transported in older, survival factor-independent sympathetic neurons, and is much less effective at inducing apoptosis in these neurons. Importantly, deletion of either neuropilin 1 or plexin A3 significantly reduces developmental cell death in the superior cervical ganglia. Taken together, a Sema3A-initiated apoptotic signaling complex regulates the apoptosis of sympathetic neurons during the period of naturally occurring cell death.
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Affiliation(s)
- Amanda B Wehner
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48109, USA Neuroscience Program, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Houari Abdesselem
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48109, USA
| | - Travis L Dickendesher
- Neuroscience Program, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Fumiyasu Imai
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45299, USA
| | - Yutaka Yoshida
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45299, USA
| | - Roman J Giger
- Neuroscience Program, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Brian A Pierchala
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48109, USA Neuroscience Program, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
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21
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Pinskey JM, Franks NE, McMellen AN, Giger RJ, Allen BL. Neuropilin-1 promotes Hedgehog signaling through a novel cytoplasmic motif. J Biol Chem 2017; 292:15192-15204. [PMID: 28667171 DOI: 10.1074/jbc.m117.783845] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/23/2017] [Indexed: 12/30/2022] Open
Abstract
Hedgehog (HH) signaling critically regulates embryonic and postnatal development as well as adult tissue homeostasis, and its perturbation can lead to developmental disorders, birth defects, and cancers. Neuropilins (NRPs), which have well-defined roles in Semaphorin and VEGF signaling, positively regulate HH pathway function, although their mechanism of action in HH signaling remains unclear. Here, using luciferase-based reporter assays, we provide evidence that NRP1 regulates HH signaling specifically at the level of GLI transcriptional activator function. Moreover, we show that NRP1 localization to the primary cilium, a key platform for HH signal transduction, does not correlate with HH signal promotion. Rather, a structure-function analysis suggests that the NRP1 cytoplasmic and transmembrane domains are necessary and sufficient to regulate HH pathway activity. Furthermore, we identify a previously uncharacterized, 12-amino acid region within the NRP1 cytoplasmic domain that mediates HH signal promotion. Overall, our results provide mechanistic insight into NRP1 function within and potentially beyond the HH signaling pathway. These insights have implications for the development of novel modulators of HH-driven developmental disorders and diseases.
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Affiliation(s)
- Justine M Pinskey
- From the Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Nicole E Franks
- From the Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Alexandra N McMellen
- From the Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Roman J Giger
- From the Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Benjamin L Allen
- From the Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
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22
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Hao Y, Frey E, Yoon C, Wong H, Nestorovski D, Holzman LB, Giger RJ, DiAntonio A, Collins C. An evolutionarily conserved mechanism for cAMP elicited axonal regeneration involves direct activation of the dual leucine zipper kinase DLK. eLife 2016; 5. [PMID: 27268300 PMCID: PMC4896747 DOI: 10.7554/elife.14048] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/12/2016] [Indexed: 11/13/2022] Open
Abstract
A broadly known method to stimulate the growth potential of axons is to elevate intracellular levels of cAMP, however the cellular pathway(s) that mediate this are not known. Here we identify the Dual Leucine-zipper Kinase (DLK, Wnd in Drosophila) as a critical target and effector of cAMP in injured axons. DLK/Wnd is thought to function as an injury ‘sensor’, as it becomes activated after axonal damage. Our findings in both Drosophila and mammalian neurons indicate that the cAMP effector kinase PKA is a conserved and direct upstream activator of Wnd/DLK. PKA is required for the induction of Wnd signaling in injured axons, and DLK is essential for the regenerative effects of cAMP in mammalian DRG neurons. These findings link two important mediators of responses to axonal injury, DLK/Wnd and cAMP/PKA, into a unified and evolutionarily conserved molecular pathway for stimulating the regenerative potential of injured axons. DOI:http://dx.doi.org/10.7554/eLife.14048.001 Adult mammals typically cannot repair damage to the nerve fibers in their brain or spinal cord. This is because these nerve cells cannot generally grow new nerve fibers. However this inability to regenerate nerve fibers is not set in stone. Instead, it can be unlocked by a second injury in nerves elsewhere in the body, the so-called “peripheral nervous system”. This process relies on an enzyme called DLK, which becomes activated in damaged nerve fibers. But how does DLK ‘sense’ damage to nerve fibers? Injuring the peripheral nervous system causes the levels of a molecule called cAMP to increase in the damaged nerve cells, and the elevated cAMP levels stimulate the nerve fibers to regenerate. However, it was not known if cAMP activates DLK, or if the two act independently of each other. By looking at the regeneration of damaged nerve fibers in fruit fly larvae, Hao et al. now show that the cAMP and DLK signaling pathways are clearly linked. Further experiments with nerve cells from mice and human cells revealed more detail about this link. Together the results showed that another enzyme called PKA activates DLK directly when cAMP levels are high. These findings reveal a unified pathway that is the key to unlocking the regenerative potential of injured nerve fibers, which has been conserved for hundreds of millions of years of evolution. Further work could now ask if the DLK enzyme is involved in the other known roles of cAMP signaling in nerve cells; or if cAMP and PKA activate DLK in other forms of nerve damage, including injuries where nerve fibers normally fail to regenerate. DOI:http://dx.doi.org/10.7554/eLife.14048.002
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Affiliation(s)
- Yan Hao
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Erin Frey
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Choya Yoon
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Hetty Wong
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Douglas Nestorovski
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Lawrence B Holzman
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Catherine Collins
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, United States
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23
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Wehner AB, Abdesselem H, Dickendesher TL, Imai F, Yoshida Y, Giger RJ, Pierchala BA. Semaphorin 3A is a retrograde cell death signal in developing sympathetic neurons. J Cell Sci 2016. [DOI: 10.1242/jcs.191593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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24
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Mironova YA, Lenk GM, Lin JP, Lee SJ, Twiss JL, Vaccari I, Bolino A, Havton LA, Min SH, Abrams CS, Shrager P, Meisler MH, Giger RJ. PI(3,5)P2 biosynthesis regulates oligodendrocyte differentiation by intrinsic and extrinsic mechanisms. eLife 2016; 5. [PMID: 27008179 PMCID: PMC4889328 DOI: 10.7554/elife.13023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/23/2016] [Indexed: 12/18/2022] Open
Abstract
Proper development of the CNS axon-glia unit requires bi-directional communication between axons and oligodendrocytes (OLs). We show that the signaling lipid phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2] is required in neurons and in OLs for normal CNS myelination. In mice, mutations of Fig4, Pikfyve or Vac14, encoding key components of the PI(3,5)P2 biosynthetic complex, each lead to impaired OL maturation, severe CNS hypomyelination and delayed propagation of compound action potentials. Primary OLs deficient in Fig4 accumulate large LAMP1+ and Rab7+ vesicular structures and exhibit reduced membrane sheet expansion. PI(3,5)P2 deficiency leads to accumulation of myelin-associated glycoprotein (MAG) in LAMP1+perinuclear vesicles that fail to migrate to the nascent myelin sheet. Live-cell imaging of OLs after genetic or pharmacological inhibition of PI(3,5)P2 synthesis revealed impaired trafficking of plasma membrane-derived MAG through the endolysosomal system in primary cells and brain tissue. Collectively, our studies identify PI(3,5)P2 as a key regulator of myelin membrane trafficking and myelinogenesis. DOI:http://dx.doi.org/10.7554/eLife.13023.001 Neurons communicate with each other through long cable-like extensions called axons. An insulating sheath called myelin (or white matter) surrounds each axon, and allows electrical impulses to travel more quickly. Cells in the brain called oligodendrocytes produce myelin. If the myelin sheath is not properly formed during development, or is damaged by injury or disease, the consequences can include paralysis, impaired thought, and loss of vision. Oligodendrocytes have complex shapes, and each can generate myelin for as many as 50 axons. Oligodendrocytes produce the building blocks of myelin inside their cell bodies, by following instructions encoded by genes within the nucleus. However, the signals that regulate the trafficking of these components to the myelin sheath are poorly understood. Mironova et al. set out to determine whether signaling molecules called phosphoinositides help oligodendrocytes to mature and move myelin building blocks from the cell bodies to remote contact points with axons. Genetic techniques were used to manipulate an enzyme complex in mice that controls the production and turnover of a phosphoinositide called PI(3,5)P2. Mironova et al. found that reducing the levels of PI(3,5)P2 in oligodendrocytes caused the trafficking of certain myelin building blocks to stall. Key myelin components instead accumulated inside bubble-like structures near the oligodendrocyte’s cell body. This showed that PI(3,5)P2 in oligodendrocytes is essential for generating myelin. Further experiments then revealed that reducing PI(3,5)P2 in the neurons themselves indirectly prevented the oligodendrocytes from maturing. This suggests that PI(3,5)P2 also takes part in communication between axons and oligodendrocytes during development of the myelin sheath. A key next step will be to identify the regulatory mechanisms that control the production of PI(3,5)P2 in oligodendrocytes and neurons. Future studies could also explore what PI(3,5)P2 acts upon inside the axons, and which signaling molecules support the maturation of oligodendrocytes. Finally, it remains unclear whether PI(3,5)P2signaling is also required for stabilizing mature myelin, and for repairing myelin after injury in the adult brain. Further work could therefore address these questions as well. DOI:http://dx.doi.org/10.7554/eLife.13023.002
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Cellular and Molecular Biology Graduate Program, University of Michigan School of Medicine, Ann Arbor, United States
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States
| | - Jing-Ping Lin
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Ilaria Vaccari
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandra Bolino
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Leif A Havton
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Sang H Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Peter Shrager
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, United States
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
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25
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Lenk GM, Frei CM, Miller AC, Wallen RC, Mironova YA, Giger RJ, Meisler MH. Rescue of neurodegeneration in the Fig4 null mouse by a catalytically inactive FIG4 transgene. Hum Mol Genet 2015; 25:340-7. [PMID: 26604144 DOI: 10.1093/hmg/ddv480] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/16/2015] [Indexed: 11/13/2022] Open
Abstract
The lipid phosphatase FIG4 is a subunit of the protein complex that regulates biosynthesis of the signaling lipid PI(3,5)P2. Mutations of FIG4 result in juvenile lethality and spongiform neurodegeneration in the mouse, and are responsible for the human disorders Charcot-Marie-Tooth disease, Yunis-Varon syndrome and polymicrogyria with seizures. We previously demonstrated that conditional expression of a wild-type FIG4 transgene in neurons is sufficient to rescue most of the abnormalities of Fig4 null mice, including juvenile lethality and extensive neurodegeneration. To evaluate the contribution of the phosphatase activity to the in vivo function of Fig4, we introduced the mutation p.Cys486Ser into the Sac phosphatase active-site motif CX5RT. Transfection of the Fig4(Cys486Ser) cDNA into cultured Fig4(-/-) fibroblasts was effective in preventing vacuolization. The neuronal expression of an NSE-Fig4(Cys486Ser) transgene in vivo prevented the neonatal neurodegeneration and juvenile lethality seen in Fig4 null mice. These observations demonstrate that the catalytically inactive FIG4 protein provides significant function, possibly by stabilization of the PI(3,5)P2 biosynthetic complex and/or localization of the complex to endolysosomal vesicles. Despite this partial rescue, later in life the NSE-Fig4(Cys486Ser) transgenic mice display significant abnormalities that include hydrocephalus, defective myelination and reduced lifespan. The late onset phenotype of the NSE-Fig4(Cys486Ser) transgenic mice demonstrates that the phosphatase activity of FIG4 has an essential role in vivo.
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Affiliation(s)
| | | | | | | | | | - Roman J Giger
- Department of Cell and Developmental Biology and Department of Neurology, University of Michigan, 4909 Buhl, Ann Arbor, MI 48109-5618, USA
| | - Miriam H Meisler
- Department of Human Genetics, Department of Neurology, University of Michigan, 4909 Buhl, Ann Arbor, MI 48109-5618, USA
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26
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Carbajal KS, Mironova Y, Ulrich-Lewis JT, Kulkarni D, Grifka-Walk HM, Huber AK, Shrager P, Giger RJ, Segal BM. Th Cell Diversity in Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis. J Immunol 2015; 195:2552-9. [PMID: 26238492 DOI: 10.4049/jimmunol.1501097] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/08/2015] [Indexed: 11/19/2022]
Abstract
Multiple sclerosis (MS) is believed to be initiated by myelin-reactive CD4(+) Th cells. IL-12-polarized Th1 cells, IL-23-polarized Th17 cells, and Th17 cells that acquire Th1 characteristics were each implicated in autoimmune pathogenesis. It is debated whether Th cells that can drive the development of demyelinating lesions are phenotypically diverse or arise from a single lineage. In the current study, we assessed the requirement of IL-12 or IL-23 stimulation, as well as Th plasticity, for the differentiation of T cells capable of inducing CNS axon damage. We found that stable murine Th1 and Th17 cells independently transfer experimental autoimmune encephalomyelitis (widely used as an animal model of MS) in the absence of IL-23 and IL-12, respectively. Plastic Th17 cells are particularly potent mediators of demyelination and axonopathy. In parallel studies, we identified MS patients who consistently mount either IFN-γ- or IL-17-skewed responses to myelin basic protein over the course of a year. Brain magnetic resonance imaging revealed that patients with mixed IFN-γ and IL-17 responses have relatively high T1 lesion burden, a measure of permanent axon damage. Our data challenge the dogma that IL-23 and Th17 plasticity are universally required for the development of experimental autoimmune encephalomyelitis. This study definitively demonstrates that autoimmune demyelinating disease can be driven by distinct Th-polarizing factors and effector subsets, underscoring the importance of a customized approach to the pharmaceutical management of MS.
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Affiliation(s)
- Kevin S Carbajal
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan, Ann Arbor, MI 48109
| | - Yevgeniya Mironova
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109; Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109
| | - Justin T Ulrich-Lewis
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan, Ann Arbor, MI 48109
| | - Deven Kulkarni
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan, Ann Arbor, MI 48109
| | - Heather M Grifka-Walk
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan, Ann Arbor, MI 48109; Graduate Program in Immunology, University of Michigan, Ann Arbor, MI 48109
| | - Amanda K Huber
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan, Ann Arbor, MI 48109
| | - Peter Shrager
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, NY 14642; and
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109; Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109
| | - Benjamin M Segal
- Holtom-Garrett Program in Neuroimmunology, Department of Neurology, University of Michigan, Ann Arbor, MI 48109; Graduate Program in Immunology, University of Michigan, Ann Arbor, MI 48109; Neurology Service, VA Ann Arbor Healthcare System, Ann Arbor, MI 48105
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27
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Abstract
The growth inhibitory nature of injured adult mammalian central nervous system (CNS) tissue constitutes a major barrier to robust axonal outgrowth and functional recovery following trauma or disease. Prototypic CNS regeneration inhibitors are broadly expressed in the healthy and injured brain and spinal cord and include myelin-associated glycoprotein (MAG), the reticulon family member NogoA, oligodendrocyte myelin glycoprotein (OMgp), and chondroitin sulfate proteoglycans (CSPGs). These structurally diverse molecules strongly inhibit neurite outgrowth in vitro, and have been most extensively studied in the context of nervous system injury in vivo. The physiological role of CNS regeneration inhibitors in the naïve, or uninjured, CNS remains less well understood, but has received growing attention in recent years and is the focus of this review. CNS regeneration inhibitors regulate myelin development and axon stability, consolidate neuronal structure shaped by experience, and limit activity-dependent modification of synaptic strength. Altered function of CNS regeneration inhibitors is associated with neuropsychiatric disorders, suggesting crucial roles in brain development and health.
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Affiliation(s)
- Katherine T Baldwin
- Department of Cell and Developmental Biology, University of Michigan School of Medicine Ann Arbor, MI, USA ; Cellular and Molecular Biology Graduate Program, University of Michigan School of Medicine Ann Arbor, MI, USA
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine Ann Arbor, MI, USA ; Department of Neurology, University of Michigan School of Medicine Ann Arbor, MI, USA
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Duan Y, Wang SH, Song J, Mironova Y, Ming GL, Kolodkin AL, Giger RJ. Semaphorin 5A inhibits synaptogenesis in early postnatal- and adult-born hippocampal dentate granule cells. eLife 2014; 3. [PMID: 25313870 PMCID: PMC4236683 DOI: 10.7554/elife.04390] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 10/13/2014] [Indexed: 12/20/2022] Open
Abstract
Human SEMAPHORIN 5A (SEMA5A) is an autism susceptibility gene; however, its function in brain development is unknown. In this study, we show that mouse Sema5A negatively regulates synaptogenesis in early, developmentally born, hippocampal dentate granule cells (GCs). Sema5A is strongly expressed by GCs and regulates dendritic spine density in a cell-autonomous manner. In the adult mouse brain, newly born Sema5A-/- GCs show an increase in dendritic spine density and increased AMPA-type synaptic responses. Sema5A signals through PlexinA2 co-expressed by GCs, and the PlexinA2-RasGAP activity is necessary to suppress spinogenesis. Like Sema5A-/- mutants, PlexinA2-/- mice show an increase in GC glutamatergic synapses, and we show that Sema5A and PlexinA2 genetically interact with respect to GC spine phenotypes. Sema5A-/- mice display deficits in social interaction, a hallmark of autism-spectrum-disorders. These experiments identify novel intra-dendritic Sema5A/PlexinA2 interactions that inhibit excitatory synapse formation in developmentally born and adult-born GCs, and they provide support for SEMA5A contributions to autism-spectrum-disorders.
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Affiliation(s)
- Yuntao Duan
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Shih-Hsiu Wang
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Juan Song
- Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Yevgeniya Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Guo-li Ming
- Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Alex L Kolodkin
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
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Vaccari I, Carbone A, Previtali SC, Mironova YA, Alberizzi V, Noseda R, Rivellini C, Bianchi F, Del Carro U, D'Antonio M, Lenk GM, Wrabetz L, Giger RJ, Meisler MH, Bolino A. Loss of Fig4 in both Schwann cells and motor neurons contributes to CMT4J neuropathy. Hum Mol Genet 2014; 24:383-96. [PMID: 25187576 PMCID: PMC4275070 DOI: 10.1093/hmg/ddu451] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mutations of FIG4 are responsible for Yunis-Varón syndrome, familial epilepsy with polymicrogyria, and Charcot-Marie-Tooth type 4J neuropathy (CMT4J). Although loss of the FIG4 phospholipid phosphatase consistently causes decreased PtdIns(3,5)P2 levels, cell-specific sensitivity to partial loss of FIG4 function may differentiate FIG4-associated disorders. CMT4J is an autosomal recessive neuropathy characterized by severe demyelination and axonal loss in human, with both motor and sensory involvement. However, it is unclear whether FIG4 has cell autonomous roles in both motor neurons and Schwann cells, and how loss of FIG4/PtdIns(3,5)P2-mediated functions contribute to the pathogenesis of CMT4J. Here, we report that mice with conditional inactivation of Fig4 in motor neurons display neuronal and axonal degeneration. In contrast, conditional inactivation of Fig4 in Schwann cells causes demyelination and defects in autophagy-mediated degradation. Moreover, Fig4-regulated endolysosomal trafficking in Schwann cells is essential for myelin biogenesis during development and for proper regeneration/remyelination after injury. Our data suggest that impaired endolysosomal trafficking in both motor neurons and Schwann cells contributes to CMT4J neuropathy.
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Affiliation(s)
- Ilaria Vaccari
- Division of Neuroscience, INSPE-Institute of Experimental Neurology
| | | | - Stefano Carlo Previtali
- Division of Neuroscience, INSPE-Institute of Experimental Neurology Department of Neurology and
| | | | | | - Roberta Noseda
- Division of Neuroscience, INSPE-Institute of Experimental Neurology
| | | | - Francesca Bianchi
- Division of Neuroscience, INSPE-Institute of Experimental Neurology Department of Neurology and
| | - Ubaldo Del Carro
- Division of Neuroscience, INSPE-Institute of Experimental Neurology Department of Neurology and
| | - Maurizio D'Antonio
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA and
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, State University of New York, Buffalo, NY 14203, USA
| | | | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA and
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Murthy R, Kim J, Sun X, Giger RJ, Fink DJ, Mata M. Post-transcriptional regulation of GABAB receptor and GIRK1 channels by Nogo receptor 1. Mol Brain 2013; 6:30. [PMID: 23829864 PMCID: PMC3734105 DOI: 10.1186/1756-6606-6-30] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 07/01/2013] [Indexed: 11/10/2022] Open
Abstract
Background Type B GABA receptors (GABA Rs) play a critical role in synaptic transmission. We carried out studies to determine whether neuronal cell surface expression of GABAB-Rs might be regulated by the Nogo receptor 1 (NgR1). Results siRNA knock-down of NgR1 resulted in a selective increase of GABAB R1 and GABAB R2 protein without altering the expression of GABAA receptor or GAD65. The increase in GABAB receptor subunits was unaccompanied by a change in mRNA, but inhibition of mTOR by rapamycin blocked the increase in GABAB protein. NgR1 siRNA also caused an increase in G protein coupled inwardly rectifying potassium channel (GIRK1). The increase in GABAB receptor and GIRK1 channel proteins was in the plasma membrane, determined by cell surface biotinylation. In NgR1 knockout mice, the amount of GABAB R2 and GIRK1 in hippocampus-derived synaptosomes was increased. Conclusions Together these findings suggest that NgR1 mediated modulation of synaptic transmission may be accomplished, at least in part, through modulation of G protein coupled receptors and channels.
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Affiliation(s)
- Rachana Murthy
- Department of Neurology, University of Michigan and VA Ann Arbor Healthcare System-Neurology and GRECC, 5027 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
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Mironova YA, Giger RJ. Where no synapses go: gatekeepers of circuit remodeling and synaptic strength. Trends Neurosci 2013; 36:363-73. [PMID: 23642707 DOI: 10.1016/j.tins.2013.04.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 02/07/2023]
Abstract
Growth inhibitory molecules in the adult mammalian central nervous system (CNS) have been implicated in the blocking of axonal sprouting and regeneration following injury. Prominent CNS regeneration inhibitors include Nogo-A, oligodendrocyte myelin glycoprotein (OMgp), and chondroitin sulfate proteoglycans (CSPGs), and a key question concerns their physiological role in the naïve CNS. Emerging evidence suggests novel functions in dendrites and at synapses of glutamatergic neurons. CNS regeneration inhibitors target the neuronal actin cytoskeleton to regulate dendritic spine maturation, long-term synapse stability, and Hebbian forms of synaptic plasticity. This is accomplished in part by antagonizing plasticity-promoting signaling pathways activated by neurotrophic factors. Altered function of CNS regeneration inhibitors is associated with mental illness and loss of long-lasting memory, suggesting unexpected and novel physiological roles for these molecules in brain health.
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, 3065 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
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Stiles TL, Dickendesher TL, Gaultier A, Fernandez-Castaneda A, Mantuano E, Giger RJ, Gonias SL. LDL receptor-related protein-1 is a sialic-acid-independent receptor for myelin-associated glycoprotein that functions in neurite outgrowth inhibition by MAG and CNS myelin. J Cell Sci 2012; 126:209-20. [PMID: 23132925 DOI: 10.1242/jcs.113191] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In the injured adult mammalian central nervous system (CNS), products are generated that inhibit neuronal sprouting and regeneration. In recent years, most attention has focused on the myelin-associated inhibitory proteins (MAIs) Nogo-A, OMgp, and myelin-associated glycoprotein (MAG). Binding of MAIs to neuronal cell-surface receptors leads to activation of RhoA, growth cone collapse, and neurite outgrowth inhibition. In the present study, we identify low-density lipoprotein (LDL) receptor-related protein-1 (LRP1) as a high-affinity, endocytic receptor for MAG. In contrast with previously identified MAG receptors, binding of MAG to LRP1 occurs independently of terminal sialic acids. In primary neurons, functional inactivation of LRP1 with receptor-associated protein, depletion by RNA interference (RNAi) knock-down, or LRP1 gene deletion is sufficient to significantly reverse MAG and myelin-mediated inhibition of neurite outgrowth. Similar results are observed when LRP1 is antagonized in PC12 and N2a cells. By contrast, inhibiting LRP1 does not attenuate inhibition of neurite outgrowth caused by chondroitin sulfate proteoglycans. Mechanistic studies in N2a cells showed that LRP1 and p75NTR associate in a MAG-dependent manner and that MAG-mediated activation of RhoA may involve both LRP1 and p75NTR. LRP1 derivatives that include the complement-like repeat clusters CII and CIV bind MAG and other MAIs. When CII and CIV were expressed as Fc-fusion proteins, these proteins, purified full-length LRP1 and shed LRP1 all attenuated the inhibition of neurite outgrowth caused by MAG and CNS myelin in primary neurons. Collectively, our studies identify LRP1 as a novel MAG receptor that functions in neurite outgrowth inhibition.
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Affiliation(s)
- Travis L Stiles
- Department of Pathology, University of California San Diego, La Jolla, CA 92093, USA
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33
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Ferguson CJ, Lenk GM, Jones JM, Grant AE, Winters JJ, Dowling JJ, Giger RJ, Meisler MH. Neuronal expression of Fig4 is both necessary and sufficient to prevent spongiform neurodegeneration. Hum Mol Genet 2012; 21:3525-34. [PMID: 22581779 DOI: 10.1093/hmg/dds179] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
FIG4 is a ubiquitously expressed phosphatase that, in complex with FAB1/PIKFYVE and VAC14, regulates the biosynthesis of the signaling lipid PI(3,5)P(2). Null mutation of Fig4 in the mouse results in spongiform degeneration of brain and peripheral ganglia, defective myelination and juvenile lethality. Partial loss-of-function of human FIG4 results in a severe form of Charcot-Marie-Tooth neuropathy. Neurons from null mice contain enlarged vacuoles derived from the endosome/lysosome pathway, and astrocytes accumulate proteins involved in autophagy. Other cellular defects include astrogliosis and microgliosis. To distinguish the contributions of neurons and glia to spongiform degeneration in the Fig4 null mouse, we expressed Fig4 under the control of the neuron-specific enolase promoter and the astrocyte-specific glial fibrillary acidic protein promoter in transgenic mice. Neuronal expression of Fig4 was sufficient to rescue cellular and neurological phenotypes including spongiform degeneration, gliosis and juvenile lethality. In contrast, expression of Fig4 in astrocytes prevented accumulation of autophagy markers and microgliosis but did not prevent spongiform degeneration or lethality. To confirm the neuronal origin of spongiform degeneration, we generated a floxed allele of Fig4 and crossed it with mice expressing the Cre recombinase from the neuron-specific synapsin promoter. Mice with conditional inactivation of Fig4 in neurons developed spongiform degeneration and the full spectrum of neurological abnormalities. The data demonstrate that expression of Fig4 in neurons is necessary and sufficient to prevent spongiform degeneration. Therapy for patients with FIG4 deficiency will therefore require correction of the deficiency in neurons.
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Affiliation(s)
- C J Ferguson
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-6518, USA
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34
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Dickendesher TL, Baldwin KT, Mironova YA, Koriyama Y, Raiker SJ, Askew KL, Wood A, Geoffroy CG, Zheng B, Liepmann CD, Katagiri Y, Benowitz LI, Geller HM, Giger RJ. NgR1 and NgR3 are receptors for chondroitin sulfate proteoglycans. Nat Neurosci 2012; 15:703-12. [PMID: 22406547 PMCID: PMC3337880 DOI: 10.1038/nn.3070] [Citation(s) in RCA: 338] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 02/06/2012] [Indexed: 12/17/2022]
Abstract
In the adult mammalian CNS, chondroitin sulfate proteoglycans (CSPGs) and myelin–associated inhibitors (MAIs) stabilize neuronal structure and restrict compensatory sprouting following injury. The Nogo receptor family members NgR1 and NgR2 bind to MAIs and have been implicated in neuronal inhibition. Here we show that NgR1 and NgR3 bind with high–affinity to the glycosaminoglycan moiety of proteoglycans and participate in CSPG inhibition in cultured neurons. Nogo receptor triple mutants (NgR123−/−), but not single mutants, show enhanced axonal regeneration following retro–orbital optic nerve crush injury. The combined loss of NgR1 and NgR3 (NgR13−/−), but not NgR1 and NgR2 (NgR12−/−), is sufficient to mimic the NgR123−/− regeneration phenotype. Regeneration in NgR13−/− mice is further enhanced by simultaneous ablation of RPTPσ, a known CSPG receptor. Collectively, these results identify NgR1 and NgR3 as novel CSPG receptors, demonstrate functional redundancy among CSPG receptors, and provide unexpected evidence for shared mechanisms of MAI and CSPG inhibition.
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Affiliation(s)
- Travis L Dickendesher
- Neuroscience Program, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
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35
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Dickendesher TL, Giger RJ. VEGF shows its attractive side at the midline. Neuron 2011; 70:808-12. [PMID: 21658576 DOI: 10.1016/j.neuron.2011.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Vascular endothelial growth factor (VEGF) family members are best known for their powerful mitotic and angiogenic activities toward endothelial cells. Two independent studies in this issue of Neuron now provide compelling evidence that VEGF-A secreted at the CNS midline functions as an attractant for developing axons of spinal commissural neurons and contralaterally projecting retinal ganglion cells.
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Affiliation(s)
- Travis L Dickendesher
- Neuroscience Program, University of Michigan School of Medicine, 3065 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
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36
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Matsuoka RL, Chivatakarn O, Badea TC, Samuels IS, Cahill H, Katayama KI, Kumer S, Suto F, Chédotal A, Peachey NS, Nathans J, Yoshida Y, Giger RJ, Kolodkin AL. Class 5 transmembrane semaphorins control selective Mammalian retinal lamination and function. Neuron 2011; 71:460-73. [PMID: 21835343 PMCID: PMC3164552 DOI: 10.1016/j.neuron.2011.06.009] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2011] [Indexed: 11/15/2022]
Abstract
In the vertebrate retina, neurites from distinct neuronal cell types are constrained within the plexiform layers, allowing for establishment of retinal lamination. However, the mechanisms by which retinal neurites are segregated within the inner or outer plexiform layers are not known. We find that the transmembrane semaphorins Sema5A and Sema5B constrain neurites from multiple retinal neuron subtypes within the inner plexiform layer (IPL). In Sema5A⁻/⁻; Sema5B⁻/⁻ mice, retinal ganglion cells (RGCs) and amacrine and bipolar cells exhibit severe defects leading to neurite mistargeting into the outer portions of the retina. These targeting abnormalities are more prominent in the outer (OFF) layers of the IPL and result in functional defects in select RGC response properties. Sema5A and Sema5B inhibit retinal neurite outgrowth through PlexinA1 and PlexinA3 receptors both in vitro and in vivo. These findings define a set of ligands and receptors required for the establishment of inner retinal lamination and function.
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Affiliation(s)
- Ryota L. Matsuoka
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Onanong Chivatakarn
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Tudor C. Badea
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ivy S. Samuels
- Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Hugh Cahill
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kei-ichi Katayama
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | | | - Fumikazu Suto
- Departments of Ultrastructural Research, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
| | - Alain Chédotal
- Institut National de la Santé et de la Recherche Médicale (INSERM), UMR S968, Institut de la Vision, F-75012 Paris, France
- Université Pierre et Marie Curie (UPMC) Paris VI, UMR S968, Institut de la Vision, F-75012 Paris, France
- Centre National de la Recherche Scientifique (CNRS) UMR 7210, Institut de la Vision, F-75012 Paris, France
| | - Neal S. Peachey
- Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
- Research Service, Cleveland VA Medical Center, Cleveland, OH 44106, USA
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yutaka Yoshida
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Roman J. Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alex L. Kolodkin
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Abstract
The inhibition of axon regeneration upon mechanical injury is dependent on interactions between Nogo receptors (NgRs) and their myelin-derived ligands. NgRs are composed of a leucine-rich repeat (LRR) region, thought to be structurally similar among the different isoforms of the receptor, and a divergent "stalk" region. It has been shown by others that the LRR and stalk regions of NgR1 and NgR2 have distinct roles in conferring binding affinity to the myelin associated glycoprotein (MAG) in vivo. Here, we show that purified recombinant full length NgR1 and NgR2 maintain significantly higher binding affinity for purified MAG as compared to the isolated LRR region of either NgR1 or NgR2. We also present the crystal structure of the LRR and part of the stalk regions of NgR2 and compare it to the previously reported NgR1 structure with respect to the distinct signaling properties of the two receptor isoforms.
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Affiliation(s)
- Mariya Semavina
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York 10065, USA
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Lenk GM, Ferguson CJ, Chow CY, Jin N, Jones JM, Grant AE, Zolov SN, Winters JJ, Giger RJ, Dowling JJ, Weisman LS, Meisler MH. Pathogenic mechanism of the FIG4 mutation responsible for Charcot-Marie-Tooth disease CMT4J. PLoS Genet 2011; 7:e1002104. [PMID: 21655088 PMCID: PMC3107197 DOI: 10.1371/journal.pgen.1002104] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 04/08/2011] [Indexed: 11/18/2022] Open
Abstract
CMT4J is a severe form of Charcot-Marie-Tooth neuropathy caused by mutation of the phosphoinositide phosphatase FIG4/SAC3. Affected individuals are compound heterozygotes carrying the missense allele FIG4-I41T in combination with a null allele. Analysis using the yeast two-hybrid system demonstrated that the I41T mutation impairs interaction of FIG4 with the scaffold protein VAC14. The critical role of this interaction was confirmed by the demonstration of loss of FIG4 protein in VAC14 null mice. We developed a mouse model of CMT4J by expressing a Fig4-I41T cDNA transgene on the Fig4 null background. Expression of the mutant transcript at a level 5× higher than endogenous Fig4 completely rescued lethality, whereas 2× expression gave only partial rescue, providing a model of the human disease. The level of FIG4-I41T protein in transgenic tissues is only 2% of that predicted by the transcript level, as a consequence of the protein instability caused by impaired interaction of the mutant protein with VAC14. Analysis of patient fibroblasts demonstrated a comparably low level of mutant I41T protein. The abundance of FIG4-I41T protein in cultured cells is increased by treatment with the proteasome inhibitor MG-132. The data demonstrate that FIG4-I41T is a hypomorphic allele encoding a protein that is unstable in vivo. Expression of FIG4-I41T protein at 10% of normal level is sufficient for long-term survival, suggesting that patients with CMT4J could be treated by increased production or stabilization of the mutant protein. The transgenic model will be useful for testing in vivo interventions to increase the abundance of the mutant protein. Charcot-Marie-Tooth disease type 4J is a severe neurological disorder with childhood or adult onset and progression to loss of mobility and death. Patients inherit a mutation that changes amino acid residue 41 of the FIG4 protein from isoleucine to threonine. We report that this mutation destabilizes the FIG4 protein by blocking its interaction with a stabilizing protein partner. We developed a mouse model of CMT4J and found that a low level of expression of the mutant protein, 10% of wildtype level, is sufficient to prevent lethality. This work provides the scientific basis for development of a directed treatment for this rare, lethal disorder.
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Affiliation(s)
- Guy M. Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Cole J. Ferguson
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Clement Y. Chow
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Natsuko Jin
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Julie M. Jones
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Adrienne E. Grant
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sergey N. Zolov
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jesse J. Winters
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Roman J. Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - James J. Dowling
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lois S. Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Miriam H. Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Minor KH, Bournat JC, Toscano N, Giger RJ, Davies SJA. Decorin, erythroblastic leukaemia viral oncogene homologue B4 and signal transducer and activator of transcription 3 regulation of semaphorin 3A in central nervous system scar tissue. ACTA ACUST UNITED AC 2010; 134:1140-55. [PMID: 21115466 DOI: 10.1093/brain/awq304] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Scar tissue at sites of traumatic injury in the adult central nervous system presents a combined physical and molecular impediment to axon regeneration. Of multiple known central nervous system scar associated axon growth inhibitors, semaphorin 3A has been shown to be strongly expressed by invading leptomeningeal fibroblasts. We have previously demonstrated that infusion of the small leucine-rich proteoglycan decorin results in major suppression of several growth inhibitory chondroitin sulphate proteoglycans and growth of adult sensory axons across acute spinal cord injuries. Furthermore, decorin treatment of leptomeningeal fibroblasts significantly increases their ability to support neurite growth of co-cultured adult dorsal root ganglion neurons. In the present study we show that decorin has the ability to suppress semaphorin 3A expression within adult rat cerebral cortex scar tissue and in primary leptomeningeal fibroblasts in vitro. Infusion of decorin core protein for eight days resulted in a significant reduction of semaphorin 3A messenger RNA expression within injury sites compared with saline-treated control animals. Both in situ hybridization and immunostaining confirmed that semaphorin 3A messenger RNA expression and protein levels are significantly reduced in decorin-treated animals. Similarly, decorin treatment decreased the expression of semaphorin 3A messenger RNA in cultured rat leptomeningeal fibroblasts compared with untreated cells. Mechanistic studies revealed that decorin-mediated suppression of semaphorin 3A critically depends on erythroblastic leukaemia viral oncogene homologue B4 and signal transducer and activator of transcription 3 function. Collectively, our studies show that in addition to suppressing the levels of inhibitory chondroitin sulphate proteoglycans, decorin has the ability to suppress semaphorin 3A in the injured central nervous system. Our findings provide further evidence for the use of decorin as a potential therapy for promoting axonal growth and repair in the injured adult mammalian brain and spinal cord.
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Affiliation(s)
- Kenneth H Minor
- Department of Neurosurgery, University of Colorado at Denver, Aurora, CO 80045, USA
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Li S, Overman JJ, Katsman D, Kozlov SV, Donnelly CJ, Twiss JL, Giger RJ, Coppola G, Geschwind DH, Carmichael ST. An age-related sprouting transcriptome provides molecular control of axonal sprouting after stroke. Nat Neurosci 2010; 13:1496-504. [PMID: 21057507 PMCID: PMC3059556 DOI: 10.1038/nn.2674] [Citation(s) in RCA: 251] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 09/21/2010] [Indexed: 12/15/2022]
Abstract
Stroke is an age-related disease. Recovery after stroke is associated with axonal sprouting in cortex adjacent to the infarct. The molecular program that induces a mature cortical neuron to sprout a new connection after stroke is not known. We selectively isolated neurons that sprout a new connection in cortex after stroke and compared their whole-genome expression profile to that of adjacent, non-sprouting neurons. This 'sprouting transcriptome' identified a neuronal growth program that consists of growth factor, cell adhesion, axonal guidance and cytoskeletal modifying molecules that differed by age and time point. Gain and loss of function in three distinct functional classes showed new roles for these proteins in epigenetic regulation of axonal sprouting, growth factor-dependent survival of neurons and, in the aged mouse, paradoxical upregulation of myelin and ephrin receptors in sprouting neurons. This neuronal growth program may provide new therapeutic targets and suggest mechanisms for age-related differences in functional recovery.
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Affiliation(s)
- Songlin Li
- Department of Neurology, David Geffen School of Medicine at University of California, Los Angeles, California, USA
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Abstract
It has been known for more than two decades that chondroitin sulfate proteoglycans (CSPGs) inhibit axonal growth and regeneration. In the adult nervous system, CSPGs are enriched in perineuronal nets, and their abundance is increased in reactive astrocytes following injury to brain or spinal cord. Degradation of chondroitin sulfate (CS) sugar moieties by the local infusion of the bacterial enzyme chondroitinase ABC (ChaseABC) enhances experience-dependent neuronal plasticity in the adult visual cortex and results in substantially improved behavioral outcomes after spinal cord injury (SCI). Although the positive effects of ChaseABC treatment on neuronal plasticity have been known for some time, the underlying mechanisms remained enigmatic. The receptor protein tyrosine phosphatase sigma (RPTPsigma) has now been identified as a receptor for inhibitory CSPGs. Similarly to ChaseABC treatment, functional ablation of Ptprs, the gene encoding RPTPsigma, promotes neurite outgrowth in the presence of CSPGs in vitro and enhances axonal growth into CSPG-rich scar tissue following SCI in vivo. The discovery of neuronal RPTPsigma as a receptor for inhibitory CSPGs not only provides important mechanistic clues about CSPG function, but also identifies a potential new target for enhancing axonal growth and plasticity after nervous system injury.
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Affiliation(s)
- Yuntao Duan
- Department of Cell and Developmental Biology and Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
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Giger RJ, Venkatesh K, Chivatakarn O, Raiker SJ, Robak L, Hofer T, Lee H, Rader C. Mechanisms of CNS myelin inhibition: evidence for distinct and neuronal cell type specific receptor systems. Restor Neurol Neurosci 2008; 26:97-115. [PMID: 18820405 PMCID: PMC7259427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Following injury to the adult mammalian central nervous system, regenerative growth of severed axons is very limited. The lack of neuronal repair is often associated with significant functional deficits, and depending on the severity of injury, may result in permanent paralysis distal to the site of injury. A detailed understanding of the molecular mechanisms that limit neuronal growth in the injured spinal cord is an important step toward the development of specific strategies aimed at restoring functional connectivity lost as a consequence of injury. While rapid progress is being made in defining the molecular identity of CNS growth inhibitory constituents, comparatively little is known about their receptors and downstream signaling mechanisms. Emerging new evidence suggests that the mechanisms for myelin inhibition are likely to be complex, involving multiple and distinct receptor systems that may operate in a redundant manner. Furthermore, the relative contribution of a specific ligand-receptor system to bring about growth inhibition may greatly vary among different neuronal cell types. Myelin-associated glycoprotein (MAG), for example, employs different mechanisms to inhibit neurite outgrowth of cerebellar, sensory, and retinal ganglion neurons in vitro. Nogo-A harbors distinct growth inhibitory regions, which employ different signaling mechanisms. The Nogo-66 receptor 1 (NgR1), a shared ligand binding component in a receptor complex for Nogo-66, MAG, and OMgp, participates in neuronal growth cone collapse to acutely presented myelin inhibitors, but is dispensable for longitudinal neurite outgrowth inhibition on substrate-bound Nogo-66, MAG, OMgp, or crude CNS myelin in vitro. Consistent with the idea of cell-type specific mechanisms for myelin inhibition, different types of CNS neurons possess very different regenerative capacities and respond differently to experimental treatment strategies in vivo. We speculate that differences in regenerative axonal growth among different fiber systems are a reflection of their intrinsic ability to elongate axons and their distinct cell surface receptor profiles to respond to the growth inhibitory extracellular milieu. The existence of cell type specific mechanisms to impair regenerative axonal growth in the CNS may have important implications for the development of treatment strategies. Depending on the fiber tract injured, different ligand-receptor systems may need to be targeted in order to elicit robust and long-distance regenerative axonal growth.
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Affiliation(s)
- Roman J Giger
- Center for Neural Development and Disorder, Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Chivatakarn O, Kaneko S, He Z, Tessier-Lavigne M, Giger RJ. The Nogo-66 receptor NgR1 is required only for the acute growth cone-collapsing but not the chronic growth-inhibitory actions of myelin inhibitors. J Neurosci 2007; 27:7117-24. [PMID: 17611264 PMCID: PMC6794578 DOI: 10.1523/jneurosci.1541-07.2007] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Neuronal Nogo-66 receptor 1 (NgR1) has been proposed to function as an obligatory coreceptor for the myelin-derived ligands Nogo-A, oligodendrocyte myelin glycoprotein (OMgp), and myelin-associated glycoprotein (MAG) to mediate neurite outgrowth inhibition by these ligands. To examine the contribution of neuronal NgR1 to outgrowth inhibition, we used two different strategies, genetic ablation of NgR1 through the germline and transient short hairpin RNA interference (shRNAi)-mediated knock-down. To monitor growth inhibition, two different paradigms were used, chronic presentation of substrate-bound inhibitor to measure neurite extension and acute application of soluble inhibitor to assay growth cone collapse. We find that regardless of the NgR1 genotype, membrane-bound MAG strongly inhibits neurite outgrowth of primary cerebellar, sensory, and cortical neurons. Similarly, substrate-bound OMgp strongly inhibits neurite outgrowth of NgR1 wild-type and mutant sensory neurons. Consistent with these results, shRNAi-mediated knock-down of neuronal NgR1 does not result in a substantial release of L-MAG (large MAG) inhibition. When applied acutely, however, MAG-Fc and OMgp-Fc induce a modest degree of growth cone collapse that is significantly attenuated in NgR1-null neurons compared with wild-type controls. Based on our findings and previous studies with Nogo-66, we propose that neuronal NgR1 has a circumscribed role in regulating cytoskeletal dynamics after acute exposure to soluble MAG, OMgp, or Nogo-66, but is not required for these ligands to mediate their growth-inhibitory properties in chronic outgrowth experiments. Our results thus provide unexpected evidence that the growth cone-collapsing activities and substrate growth-inhibitory activities of inhibitory ligands can be dissociated. We also conclude that chronic axon growth inhibition by myelin is mediated by NgR1-independent mechanisms.
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Affiliation(s)
- Onanong Chivatakarn
- Interdepartmental Graduate Program in Neuroscience
- Center for Aging and Developmental Biology, Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Shinjiro Kaneko
- Division of Neuroscience, Children's Hospital and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115, and
| | - Zhigang He
- Division of Neuroscience, Children's Hospital and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115, and
| | | | - Roman J. Giger
- Center for Aging and Developmental Biology, Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
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Venkatesh K, Chivatakarn O, Sheu SS, Giger RJ. Molecular dissection of the myelin-associated glycoprotein receptor complex reveals cell type-specific mechanisms for neurite outgrowth inhibition. J Cell Biol 2007; 177:393-9. [PMID: 17470639 PMCID: PMC2064823 DOI: 10.1083/jcb.200702102] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Accepted: 03/26/2007] [Indexed: 01/21/2023] Open
Abstract
Neuronal Nogo66 receptor-1 (NgR1) binds the myelin inhibitors NogoA, OMgp, and myelin-associated glycoprotein (MAG) and has been proposed to function as the ligand-binding component of a receptor complex that also includes Lingo-1, p75(NTR), or TROY. In this study, we use Vibrio cholerae neuraminidase (VCN) and mouse genetics to probe the molecular composition of the MAG receptor complex in postnatal retinal ganglion cells (RGCs). We find that VCN treatment is not sufficient to release MAG inhibition of RGCs; however, it does attenuate MAG inhibition of cerebellar granule neurons. Furthermore, the loss of p75(NTR) is not sufficient to release MAG inhibition of RGCs, but p75(NTR-/-) dorsal root ganglion neurons show enhanced growth on MAG compared to wild-type controls. Interestingly, TROY is not a functional substitute for p75(NTR) in RGCs. Finally, NgR1(-/-) RGCs are strongly inhibited by MAG. In the presence of VCN, however, NgR1(-/-) RGCs exhibit enhanced neurite growth. Collectively, our experiments reveal distinct and cell type-specific mechanisms for MAG-elicited growth inhibition.
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MESH Headings
- Animals
- Bacterial Proteins/chemistry
- CHO Cells
- Cricetinae
- Cricetulus
- GPI-Linked Proteins
- Ganglia, Spinal/chemistry
- Ganglia, Spinal/cytology
- Ganglia, Spinal/metabolism
- Mice
- Mice, Knockout
- Mice, Mutant Strains
- Multiprotein Complexes/chemistry
- Multiprotein Complexes/genetics
- Multiprotein Complexes/metabolism
- Myelin Proteins/antagonists & inhibitors
- Myelin Proteins/chemistry
- Myelin Proteins/genetics
- Myelin Proteins/metabolism
- Myelin-Associated Glycoprotein
- Neuraminidase/chemistry
- Neurites/chemistry
- Neurites/metabolism
- Nogo Proteins
- Nogo Receptor 1
- Rats
- Receptors, Cell Surface/antagonists & inhibitors
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, Nerve Growth Factor/chemistry
- Receptors, Nerve Growth Factor/genetics
- Receptors, Nerve Growth Factor/metabolism
- Receptors, Tumor Necrosis Factor/chemistry
- Receptors, Tumor Necrosis Factor/genetics
- Receptors, Tumor Necrosis Factor/metabolism
- Retinal Ganglion Cells/chemistry
- Retinal Ganglion Cells/cytology
- Retinal Ganglion Cells/metabolism
- Vibrio cholerae/enzymology
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Affiliation(s)
- Karthik Venkatesh
- Interdepartmental Graduate Program in Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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45
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Hofer T, Tangkeangsirisin W, Kennedy MG, Mage RG, Raiker SJ, Venkatesh K, Lee H, Giger RJ, Rader C. Chimeric rabbit/human Fab and IgG specific for members of the Nogo-66 receptor family selected for species cross-reactivity with an improved phage display vector. J Immunol Methods 2006; 318:75-87. [PMID: 17140598 PMCID: PMC1930160 DOI: 10.1016/j.jim.2006.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Revised: 09/08/2006] [Accepted: 10/02/2006] [Indexed: 01/25/2023]
Abstract
NgR1, NgR2, and NgR3 which constitute the Nogo-66 receptor family are primarily expressed by neurons in the central nervous system (CNS) and believed to limit axonal growth and sprouting following CNS injury. In an attempt to define the expression and decipher the function of individual members of the Nogo-66 receptor family, we previously reported the generation of selective rabbit polyclonal antibodies. Here we exploit the same immune repertoires by phage display technology to generate rabbit monoclonal antibodies (mAbs) with nanomolar affinity to epitopes that are specific for NgR1 and NgR2, respectively, but at the same time conserved between mouse, rat, and human orthologs. Employing phage display vector pC3C, a newly designed phagemid optimized for the generation and selection of Fab libraries with human constant domains, rabbit mAbs were selected from chimeric rabbit/human Fab libraries, characterized in terms of specificity, affinity, and amino acid sequence, and finally converted to chimeric rabbit/human IgG. Using immunofluorescence microscopy and immunoprecipitation, we demonstrate strong and specific recognition of cell surface bound Nogo-66 receptor family members by chimeric rabbit/human IgG. The rabbit mAbs reported here together with their amino acid sequences constitute a defined panel of species cross-reactive reagents in infinite supply which will aid investigations toward a functional role of the Nogo-66 receptor family in and beyond the CNS.
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Affiliation(s)
- Thomas Hofer
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892-1203, USA
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46
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Venkatesh K, Chivatakarn O, Lee H, Joshi PS, Kantor DB, Newman BA, Mage R, Rader C, Giger RJ. The Nogo-66 receptor homolog NgR2 is a sialic acid-dependent receptor selective for myelin-associated glycoprotein. J Neurosci 2005; 25:808-22. [PMID: 15673660 PMCID: PMC6725623 DOI: 10.1523/jneurosci.4464-04.2005] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Nogo-66 receptor (NgR1) is a promiscuous receptor for the myelin inhibitory proteins Nogo/Nogo-66, myelin-associated glycoprotein (MAG), and oligodendrocyte myelin glycoprotein (OMgp). NgR1, an axonal glycoprotein, is the founding member of a protein family composed of the structurally related molecules NgR1, NgR2, and NgR3. Here we show that NgR2 is a novel receptor for MAG and acts selectively to mediate MAG inhibitory responses. MAG binds NgR2 directly and with greater affinity than NgR1. In neurons NgR1 and NgR2 support MAG binding in a sialic acid-dependent Vibrio cholerae neuraminidase-sensitive manner. Forced expression of NgR2 is sufficient to impart MAG inhibition to neonatal sensory neurons. Soluble NgR2 has MAG antagonistic capacity and promotes neuronal growth on MAG and CNS myelin substrate in vitro. Structural studies have revealed that the NgR2 leucine-rich repeat cluster and the NgR2 "unique" domain are necessary for high-affinity MAG binding. Consistent with its role as a neuronal MAG receptor, NgR2 is an axonassociated glycoprotein. In postnatal brain NgR1 and NgR2 are strongly enriched in Triton X-100-insoluble lipid rafts. Neural expression studies of NgR1 and NgR2 have revealed broad and overlapping, yet distinct, distribution in the mature CNS. Taken together, our studies identify NgRs as a family of receptors (or components of receptors) for myelin inhibitors and provide insights into how interactions between MAG and members of the Nogo receptor family function to coordinate myelin inhibitory responses.
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Affiliation(s)
- Karthik Venkatesh
- Center for Aging and Developmental Biology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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47
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Abstract
Axon branching is vital to the development of a highly interconnected and functional nervous system. Similar to axon growth and guidance, axon branching is subject to dynamic remodeling of the neuronal cytoskeleton. Coordinated remodeling of the cytoskeleton is achieved through parallel and direct targeting of both actin filaments and a subset of highly dynamic microtubules that probe the actin-rich peripheral domains in growth cones and emerging branch sites. A growing number of extracellular cues implicated in growth cone guidance also influence axon branch behavior. Mechanistic insight into the molecular basis of growth cone steering and axon branching reveals significant similarities but also uncovers important differences between these crucial events in the establishment of neural circuits.
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Affiliation(s)
- David R Kornack
- Department of Neurobiology and Anatomy, Center for Aging and Developmental Biology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
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48
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Kantor DB, Chivatakarn O, Peer KL, Oster SF, Inatani M, Hansen MJ, Flanagan JG, Yamaguchi Y, Sretavan DW, Giger RJ, Kolodkin AL. Semaphorin 5A Is a Bifunctional Axon Guidance Cue Regulated by Heparan and Chondroitin Sulfate Proteoglycans. Neuron 2004; 44:961-75. [PMID: 15603739 DOI: 10.1016/j.neuron.2004.12.002] [Citation(s) in RCA: 267] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Revised: 11/24/2004] [Accepted: 11/29/2004] [Indexed: 10/26/2022]
Abstract
The response of neuronal growth cones to axon guidance cues depends on the developmental context in which these cues are encountered. We show here that the transmembrane protein semaphorin 5A (Sema5A) is a bifunctional guidance cue exerting both attractive and inhibitory effects on developing axons of the fasciculus retroflexus, a diencephalon fiber tract associated with limbic function. The thrombospondin repeats of Sema5A physically interact with the glycosaminoglycan portion of both chondroitin sulfate proteoglycans (CSPGs) and heparan sulfate proteoglycans (HSPGs). CSPGs function as precisely localized extrinsic cues that convert Sema5A from an attractive to an inhibitory guidance cue. Therefore, glycosaminoglycan bound guidance cues provide a molecular mechanism for CSPG-mediated inhibition of axonal extension. Further, axonal HSPGs are required for Sema5A-mediated attraction, suggesting that HSPGs are components of functional Sema5A receptors. Thus, neuronal responses to Sema5A are proteoglycan dependent and interpreted according to the biological context in which this membrane bound guidance cue is presented.
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Affiliation(s)
- David B Kantor
- Department of Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, USA
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49
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Holtmaat AJGD, Gorter JA, De Wit J, Tolner EA, Spijker S, Giger RJ, Lopes da Silva FH, Verhaagen J. Transient downregulation of Sema3A mRNA in a rat model for temporal lobe epilepsy. A novel molecular event potentially contributing to mossy fiber sprouting. Exp Neurol 2003; 182:142-50. [PMID: 12821384 DOI: 10.1016/s0014-4886(03)00035-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mossy fiber sprouting (MFS) in the hippocampal dentate gyrus is thought to play a critical role in the hyperexcitability of the hippocampus in temporal lobe epilepsy patients. The composition of molecular signals that is needed to direct this sprouting response has not yet been elucidated to a great extent. In the present study we investigated the expression profile of Sema3A mRNA and the axonal growth-associated protein GAP-43 mRNA during the process of electrically induced epileptogenesis in rats. Sema3A is an axon guidance molecule with repellent activity on dentate granule cell axons. It is produced by neurons in the entorhinal cortex, which synapse on the dendrites of dentate granule cells. Upregulation of GAP-43 expression in granule cells has often been reported in conjunction with MFS. After induction of status epilepticus, the expression of Sema3A mRNA was temporarily downregulated in the entorhinal cortex concomitantly with an upregulation of GAP-43 mRNA in dentate granule cells. In the following days, robust MFS into the dentate molecular layer was observed. When the induction of status epilepticus was incomplete the two responses appeared to dissociate, i.e., the downregulation of Sema3A mRNA did not occur, while upregulation of GAP-43 mRNA in dentate granule cells was still displayed. However, in these rats no significant MFS was observed. These findings indicate that Sema3A mRNA downregulation is temporarily correlated with MFS, while GAP-43 upregulation per se is not, and suggest that a loss of Sema3A in the molecular layer of the dentate gyrus could facilitate MFS into this area during epilepsy.
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Affiliation(s)
- Anthony J G D Holtmaat
- Graduate School of Neuroscience, Netherlands Institute for Brain Research, Amsterdam, Netherlands
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50
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Cloutier JF, Giger RJ, Koentges G, Dulac C, Kolodkin AL, Ginty DD. Neuropilin-2 mediates axonal fasciculation, zonal segregation, but not axonal convergence, of primary accessory olfactory neurons. Neuron 2002; 33:877-92. [PMID: 11906695 DOI: 10.1016/s0896-6273(02)00635-9] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The mechanisms that underlie axonal pathfinding of vomeronasal neurons from the vomeronasal organ (VNO) in the periphery to select glomeruli in the accessory olfactory bulb (AOB) are not well understood. Neuropilin-2, a receptor for secreted semaphorins, is expressed in V1R- and V3R-expressing, but not V2R-expressing, postnatal vomeronasal neurons. Analysis of the vomeronasal nerve in neuropilin-2 (npn-2) mutant mice reveals pathfinding defects at multiple choice points. Vomeronasal sensory axons are severely defasciculated and a subset innervates the main olfactory bulb (MOB). While most axons of V1R-expressing neurons reach the AOB and converge into distinct glomeruli in stereotypic locations, they are no longer restricted to their normal anterior AOB target zone. Thus, Npn-2 and candidate pheromone receptors play distinct and complementary roles in promoting the wiring and patterning of sensory neurons in the accessory olfactory system.
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Affiliation(s)
- Jean François Cloutier
- Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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