Combined neuroprotection and metabolic correction to treat leukodystrophies

Summary

Principal Investigator: ERNESTO ROQUE BONGARZONE
Abstract: DESCRIPTION (provided by applicant): Galactosylceramidase (GALC) deficiency in Krabbe disease (KD) causes toxic accumulation of galactosylsphingosine (psychosine) in myelin-forming cells, leading to demyelination of the nervous system. To reduce demyelination, current therapies seek to provide the missing enzyme to myelinating glia via infiltrating macrophages after the transplantation of bone marrow cells (BMT) from healthy donors into affected patients. Although the experience gained from this approach supports the use of BMT, KD patients suffer neurological sequelae. This suggests that the pathogenic mechanisms in KD are more complex than previously thought and that new therapeutic strategies are needed to cure KD. Experiments in our laboratory using the Twitcher mouse, a natural model for KD, indicate: 1) BMT- treated mice show neuronal and axonal damage by the time sufficient therapeutic enzyme accumulates in the nervous system [1];2) psychosine is also produced and accumulates in neurons in the absence of mutant glia, causing the blockage of fast axonal transport via the activity of protein phosphatase 1 (PP1);and 3) mutant neurons show abnormal intracellular levels of Ca linked to deregulated expression of the Na+ Ca exchanger (NCX1). These observations suggest that GALC-deficient neurons mount a stress response that contributes to the pathology and that PP1 and NCX1 are two potential key components in the mechanism that mediates axonal defects in KD. Thus, we hypothesize that the deficiency of GALC in KD not only affects myelination but also triggers intrinsic and contemporaneous defects in neurons. To test this hypothesis we propose specific experiments to modulate PP1 and NCX1 activities in Twitcher neurons. These experiments will provide proof-of-concept that neuroprotective strategies can synergize with/improve the therapeutic benefits of traditional BMT-based treatments. Specifically, we will: 1) determine whether controlled and specific reduction of neuronal PP1 activity using siRNA specific silencing protects axonal transport in mutant neurons;2) determine whether flecainide, an antiarrhythmic drug with a proven ability to reduce sodium channel firing and NCX1 activity, improves NCX1-mediated influx of calcium in axons;and 3) determine whether these neuroprotective strategies combined with metabolic correction after BMT in newborn Twitcher mice improve clinical outcome. Results from these experiments will shed light on the molecular role of PP1 and NCX1 activity mediating neuronal dysfunction in KD and will provide a unique opportunity to improve the current BMT-based metabolic corrective strategies used to treat this leukodystrophy. The insight obtained will be relevant to other lysosomal storage disorders, which like KD are associated with aggressive neurological deterioration and for which there are no available cures. PUBLIC HEALTH RELEVANCE: Krabbe disease is a lysosomal storage disease that results in demyelination of the brain and nerves in affected individuals. Some Krabbe patients are treated with hematogenous cell replacement, which delays the onset of symptoms. However, a definitive and complete cure for this disease has not been achieved and treated patients continue to undergo deterioration and neurological deficits. The role of neuronal loss in Krabbe disease is not completely understood, but a consensus is emerging that dysfunction of axons and neurons leads to permanent neurological deficits in several neurodegenerative disorders, including multiple sclerosis, Alzheimer disease, Parkinson disease and others. Our preliminary studies provide evidence that Krabbe disease is compounded by axonal defects. In addition to the loss of myelin, neurodegeneration is likely a limiting factor in reducing the efficiency of traditional therapies. Thus, a combined therapy that provides not only enzyme replacement but also neuroprotection is likely to synergize or enhance the therapeutic benefits. Our objective is to examine whether two novel neuroprotective strategies targeting specific aspects of neurodegeneration in Krabbe disease can be combined with traditional bone marrow transplantation to fully prevent development of the disease. Results of the proposed experiments will provide proof-of-concept for the design of combined neuroprotective therapies to treat human Krabbe patients and the rational basis for studies of other leukodystrophies that involve degeneration of axons and myelin.
Funding Period: 2009-09-01 - 2014-08-31
more information: NIH RePORT

Top Publications

  1. pmc Persistence of psychosine in brain lipid rafts is a limiting factor in the therapeutic recovery of a mouse model for Krabbe disease
    A B White
    Department of Anatomy and Cell Biology, University of Illinois, Chicago, Illinois, USA
    J Neurosci Res 89:352-64. 2011
  2. pmc Axonopathy is a compounding factor in the pathogenesis of Krabbe disease
    Ludovico Cantuti Castelvetri
    Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, MC512, Chicago, IL 60612, USA
    Acta Neuropathol 122:35-48. 2011
  3. pmc Psychosine induces the dephosphorylation of neurofilaments by deregulation of PP1 and PP2A phosphatases
    Ludovico Cantuti-Castelvetri
    Department of Anatomy and Cell Biology, University of Illinois, Chicago, IL 60612, USA
    Neurobiol Dis 46:325-35. 2012
  4. pmc MMP-3 mediates psychosine-induced globoid cell formation: implications for leukodystrophy pathology
    Kumiko Ijichi
    Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06510, USA
    Glia 61:765-77. 2013
  5. pmc Missense mutation in mouse GALC mimics human gene defect and offers new insights into Krabbe disease
    Gregory B Potter
    Department of Pediatrics, Oregon Health and Science University, Portland, OR 97239, USA
    Hum Mol Genet 22:3397-414. 2013
  6. pmc The sphingolipid psychosine inhibits fast axonal transport in Krabbe disease by activation of GSK3β and deregulation of molecular motors
    Ludovico Cantuti Castelvetri
    Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612, USA
    J Neurosci 33:10048-56. 2013
  7. pmc Neuronal inclusions of α-synuclein contribute to the pathogenesis of Krabbe disease
    Benjamin R Smith
    Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, University of Illinois Chicago, Chicago, IL, 60612, USA
    J Pathol 232:509-21. 2014

Detail Information

Publications9

  1. pmc Persistence of psychosine in brain lipid rafts is a limiting factor in the therapeutic recovery of a mouse model for Krabbe disease
    A B White
    Department of Anatomy and Cell Biology, University of Illinois, Chicago, Illinois, USA
    J Neurosci Res 89:352-64. 2011
    ..This work describes a mechanism that may contribute to limiting the in vivo efficacy of traditional therapies for KD...
  2. pmc Axonopathy is a compounding factor in the pathogenesis of Krabbe disease
    Ludovico Cantuti Castelvetri
    Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, MC512, Chicago, IL 60612, USA
    Acta Neuropathol 122:35-48. 2011
    ..Neuronal damage occurred at later stages, when mutant mice were moribund and demyelinated. Altogether, these findings suggest a progressive dying-back neuronal dysfunction in Twitcher mutants...
  3. pmc Psychosine induces the dephosphorylation of neurofilaments by deregulation of PP1 and PP2A phosphatases
    Ludovico Cantuti-Castelvetri
    Department of Anatomy and Cell Biology, University of Illinois, Chicago, IL 60612, USA
    Neurobiol Dis 46:325-35. 2012
    ..We propose that a psychosine-driven pathogenic mechanism through deregulated phosphotransferase activities may be involved in this process...
  4. pmc MMP-3 mediates psychosine-induced globoid cell formation: implications for leukodystrophy pathology
    Kumiko Ijichi
    Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06510, USA
    Glia 61:765-77. 2013
    ..Hence, elevated expression of MMP-3 in GLD may promote microglial responses to psychosine that may represent an important pathophysiological process in this disease and its treatment...
  5. pmc Missense mutation in mouse GALC mimics human gene defect and offers new insights into Krabbe disease
    Gregory B Potter
    Department of Pediatrics, Oregon Health and Science University, Portland, OR 97239, USA
    Hum Mol Genet 22:3397-414. 2013
    ..Furthermore, our results argue against a causative relationship between psychosine accumulation, white matter loss and gliosis...
  6. pmc The sphingolipid psychosine inhibits fast axonal transport in Krabbe disease by activation of GSK3β and deregulation of molecular motors
    Ludovico Cantuti Castelvetri
    Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612, USA
    J Neurosci 33:10048-56. 2013
    ..This study identifies psychosine as a pathogenic sphingolipid able to block fast axonal transport and is the first to provide a molecular mechanism underlying dying-back degeneration in this genetic leukodystrophy...
  7. pmc Neuronal inclusions of α-synuclein contribute to the pathogenesis of Krabbe disease
    Benjamin R Smith
    Department of Anatomy and Cell Biology, College of Medicine, University of Illinois, University of Illinois Chicago, Chicago, IL, 60612, USA
    J Pathol 232:509-21. 2014
    ..This study demonstrates the occurrence of neuronal deposits of fibrillized proteins including α-synuclein, identifying Krabbe disease as a new α-synucleinopathy...

Research Grants30

  1. Alzheimer's Disease Research Center
    Thomas J Montine; Fiscal Year: 2013
    ..Montine;Project 2: Therapeutic Effects of Intra-Nasal Insulin Detemir, Dr. Suzanne Craft;Project 3: Modulation of A peptide accumulation and neuron damage in vivo with adult bone marrow transplants, Dr. C. Dirk Keene. ..
  2. Effect of early psychosine accumulation in Krabbe Disease on CNS progenitor cells
    NICOLE JANET SCOTT; Fiscal Year: 2013
    ..abstract_text> ..
  3. Emory Alzheimer's Disease Center
    Allan I Levey; Fiscal Year: 2013
    ..abstract_text> ..
  4. Tissue injury and inflammation in MS (P50)
    Bruce D Trapp; Fiscal Year: 2013
    ..abstract_text> ..
  5. Alzheimer's Disease Research Center
    Douglas R Galasko; Fiscal Year: 2013
    ..It will provide an environment and core resources to enhance research, foster professional and community training, and coordinate interdisciplinary research. ..
  6. Center for Novel Therapeutics for HIV-Associated Cognitive Disorders
    Justin C McArthur; Fiscal Year: 2013
    ..5. To identify and validate surrogate biomarkers based on proteomics and lipomics. ..
  7. Identification of novel small molecules for CNS myelin repair
    Jianrong Li; Fiscal Year: 2013
    ..This proposed study has the potential to lead to the development of novel therapeutic interventions aimed at promoting myelin regeneration and functional recovery. ..
  8. Genetic analyses of axon transport and microtubule dynamics in Zebrafish
    Alex Nechiporuk; Fiscal Year: 2013
    ....
  9. INITIATION OF HUMAN LABOR: PREVENTION OF PREMATURITY
    Carole R Mendelson; Fiscal Year: 2013
    ..We propose that these interrelated projects, carried out by a highly interactive research team, will achieve the long-range goals of this Program and contribute to a reduction in the incidence of preterm birth. ..
  10. Neuroprotection and Myelin Repair Mechanisms in Multiple Sclerosis
    Inderjit Singh; Fiscal Year: 2013
    ....
  11. Baylor Intellectual and Developmental Disabilities Research Center
    Huda Y Zoghbi; Fiscal Year: 2013
    ..abstract_text> ..
  12. CYTOKINES IN GLIAL CELLS AND EAE BRAIN
    Inderjit Singh; Fiscal Year: 2013
    ..These studies will identify therapeutic targets for induction of myelin repair in MS and these findings should be applicable to other related neurodegenerative diseases. ..
  13. UCLA Alzheimer's Disease Research Center
    David B Teplow; Fiscal Year: 2013
    ..Innovations in advancing research are proposed in each Core of this proposal. Each core has responded to criticisms and recommendations from the 2008 review in this renewal application. ..
  14. Gamma-Secretase and Myelin: A Paradigm Shift in Brain Disorders
    Gang Yu; Fiscal Year: 2013
    ..As such this work represents a new way of thinking about brain functions and disorders. ..