myelin-basic-protein and Movement-Disorders

Myelination is a late developmental process regulated by a set of inhibitory and stimulatory factors, including extracellular matrix components. Accordingly, chondroitin sulfate proteoglycans (CSPGs) act as negative regulators of myelination processes. A disintegrin and metalloproteinase with thrombospondin motifs type 4 (ADAMTS-4) is an extracellular protease capable of degrading CSPGs. Although exogenous ADAMTS-4 has been proven to be beneficial in several models of central nervous system (CNS) injuries, the physiological functions of endogenous ADAMTS-4 remain poorly understood. We first used Adamts4/LacZ reporter mice to reveal that ADAMTS-4 is strongly expressed in the CNS, especially in the white matter, with a cellular profile restricted to mature oligodendrocytes. Interestingly, we evidenced an abnormal myelination in Adamts4

Topics: ADAMTS4 Protein; Animals; Animals, Newborn; beta-Galactosidase; Calcium-Binding Proteins; Corpus Callosum; Disease Models, Animal; Evoked Potentials, Somatosensory; Gait Disorders, Neurologic; Locomotion; Male; Mice; Mice, Transgenic; Microfilament Proteins; Microscopy, Electron; Movement Disorders; Myelin Basic Protein; Nerve Tissue Proteins; Oligodendroglia; Receptor, Platelet-Derived Growth Factor alpha; Statistics, Nonparametric

Infection and sepsis are associated with brain white matter injury in preterm infants and the subsequent development of cerebral palsy.. In the present study, we used a neonatal mouse sepsis-induced white matter injury model to determine the contribution of different T cell subsets (αβT cells and γδT cells) to white matter injury and consequent behavioral changes. C57BL/6J wild-type (WT), T cell receptor (TCR) δ-deficient (Tcrd. White matter development was normal in Tcrd. Our results suggest that γδT cells but not αβT cells contribute to sepsis-induced white matter injury and subsequent motor function abnormalities in early life. Modulating the activity of γδT cells in the early stages of preterm white matter injury might represent a novel therapeutic strategy for the treatment of perinatal brain injury.

Topics: Animals; Animals, Newborn; Anxiety; Brain; Cytokines; Disease Models, Animal; Gait; Gene Expression Regulation, Developmental; Leukoencephalopathies; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Mice, Transgenic; Movement Disorders; Myelin Basic Protein; Receptors, Antigen, T-Cell, alpha-beta; Receptors, Antigen, T-Cell, gamma-delta; Sepsis; Spleen; T-Lymphocyte Subsets

Pelizaeus-Merzbacher-like disease or hypomyelinating leukodystrophy-2 is an autosomal recessively inherited leukodystrophy with childhood onset resulting from mutations in the gene encoding the gap junction protein connexin 47 (Cx47, encoded by GJC2). Cx47 is expressed specifically in oligodendrocytes and is crucial for gap junctional communication throughout the central nervous system. Previous studies confirmed that a cell autonomous loss-of-function mechanism underlies hypomyelinating leukodystrophy-2 and that transgenic oligodendrocyte-specific expression of another connexin, Cx32 (GJB1), can restore gap junctions in oligodendrocytes to achieve correction of the pathology in a disease model. To develop an oligodendrocyte-targeted gene therapy, we cloned the GJC2/Cx47 gene under the myelin basic protein promoter and used an adeno-associated viral vector (AAV.MBP.Cx47myc) to deliver the gene to postnatal Day 10 mice via a single intracerebral injection in the internal capsule area. Lasting Cx47 expression specifically in oligodendrocytes was detected in Cx47 single knockout and Cx32/Cx47 double knockout mice up to 12 weeks post-injection, including the corpus callosum and the internal capsule but also in more distant areas of the cerebrum and in the spinal cord. Application of this oligodendrocyte-targeted somatic gene therapy at postnatal Day 10 in groups of double knockout mice, a well characterized model of hypomyelinating leukodystrophy-2, resulted in significant improvement in motor performance and coordination at 1 month of age in treated compared to mock-treated mice, as well as prolonged survival. Furthermore, immunofluorescence and morphological analysis revealed improvement in demyelination, oligodendrocyte apoptosis, inflammation, and astrogliosis, all typical features of this leukodystrophy model in both brain and spinal cord. Functional dye transfer analysis confirmed the re-establishment of oligodendrocyte gap junctional connectivity in treated as opposed to untreated mice. These results provide a significant advance in the development of oligodendrocyte-cell specific gene therapy. Adeno-associated viral vectors can be used to target therapeutic expression of a myelin gene to oligodendrocytes. We show evidence for the first somatic gene therapy approach to treat hypomyelinating leukodystrophy-2 preclinically, providing a potential treatment for this and similar forms of leukodystrophies.

Topics: Animals; Animals, Newborn; Antigens, CD; Apoptosis; Connexins; Dependovirus; Disease Models, Animal; Gap Junction beta-1 Protein; Gene Expression Regulation; Genetic Therapy; Green Fluorescent Proteins; Humans; Leukoencephalopathies; Mice; Mice, Inbred C57BL; Mice, Transgenic; Movement Disorders; Myelin Basic Protein; Myelin Sheath; Oligodendroglia; Psychomotor Performance

Devic's neuromyelitis optica (NMO) is an autoimmune astrocytopathy, associated with central nervous system inflammation, demyelination, and neuronal injury. Several studies confirmed that autoantibodies directed against aquaporin-4 (AQP4-IgG) are relevant in the pathogenesis of NMO, mainly through complement-dependent toxicity leading to astrocyte death. However, the effect of the autoantibody per se and the exact role of intrathecal AQP4-IgG are still controversial.. To explore the intrinsic effect of intrathecal AQP4-IgG, independent from additional inflammatory effector mechanisms, and to evaluate its clinical impact, we developed a new animal model, based on a prolonged infusion of purified immunoglobulins from NMO patient (IgG(AQP4+), NMO-rat) and healthy individual as control (Control-rat) in the cerebrospinal fluid (CSF) of live rats.. We showed that CSF infusion of purified immunoglobulins led to diffusion in the brain, spinal cord, and optic nerves, the targeted structures in NMO. This was associated with astrocyte alteration in NMO-rats characterized by loss of aquaporin-4 expression in the spinal cord and the optic nerves compared to the Control-rats (p = 0.001 and p = 0.02, respectively). In addition, glutamate uptake tested on vigil rats was dramatically reduced in NMO-rats (p = 0.001) suggesting that astrocytopathy occurred in response to AQP4-IgG diffusion. In parallel, myelin was altered, as shown by the decrease of myelin basic protein staining by up to 46 and 22 % in the gray and white matter of the NMO-rats spinal cord, respectively (p = 0.03). Loss of neurofilament positive axons in NMO-rats (p = 0.003) revealed alteration of axonal integrity. Then, we investigated the clinical consequences of such alterations on the motor behavior of the NMO-rats. In a rotarod test, NMO-rats performance was lower compared to the controls (p = 0.0182). AQP4 expression, and myelin and axonal integrity were preserved in AQP4-IgG-depleted condition. We did not find a major immune cell infiltration and microglial activation nor complement deposition in the central nervous system, in our model.. We establish a link between motor-deficit, NMO-like lesions and astrocytopathy mediated by intrathecal AQP4-IgG. Our study validates the concept of the intrinsic effect of autoantibody against surface antigens and offers a model for testing antibody and astrocyte-targeted therapies in NMO.

Topics: Animals; Animals, Newborn; Aquaporin 4; Astrocytes; Axons; Cells, Cultured; Cerebrospinal Fluid; Disease Models, Animal; Glial Fibrillary Acidic Protein; Glutamic Acid; Humans; Immunoglobulin G; Movement Disorders; Myelin Basic Protein; Myelin Sheath; Neuromyelitis Optica; Optic Nerve; Rats; Spinal Cord

Breakdown of neuro-glial N-acetyl-aspartate (NAA) metabolism results in the failure of developmental myelination, manifest in the congenital pediatric leukodystrophy Canavan disease caused by mutations to the sole NAA catabolizing enzyme aspartoacylase. Canavan disease is a major point of focus for efforts to define NAA function, with available evidence suggesting NAA serves as an acetyl donor for fatty acid synthesis during myelination. Elevated NAA is a diagnostic hallmark of Canavan disease, which contrasts with a broad spectrum of alternative neurodegenerative contexts in which levels of NAA are inversely proportional to pathological progression. Recently generated data in the nur7 mouse model of Canavan disease suggests loss of aspartoacylase function results in compromised energetic integrity prior to oligodendrocyte death, abnormalities in myelin content, spongiform degeneration, and motor deficit. The present study utilized a next-generation "oligotropic" adeno-associated virus vector (AAV-Olig001) to quantitatively assess the impact of aspartoacylase reconstitution on developmental myelination. AAV-Olig001-aspartoacylase promoted normalization of NAA, increased bioavailable acetyl-CoA, and restored energetic balance within a window of postnatal development preceding gross histopathology and deteriorating motor function. Long-term effects included increased oligodendrocyte numbers, a global increase in myelination, reversal of vacuolation, and rescue of motor function. Effects on brain energy observed following AAV-Olig001-aspartoacylase gene therapy are shown to be consistent with a metabolic profile observed in mild cases of Canavan disease, implicating NAA in the maintenance of energetic integrity during myelination via oligodendroglial aspartoacylase.

Topics: Amidohydrolases; Animals; Aspartic Acid; Autophagy-Related Proteins; Basic Helix-Loop-Helix Transcription Factors; Brain; Canavan Disease; Child; Child, Preschool; Dependovirus; Disease Progression; Energy Metabolism; Female; Gene Expression Regulation; Green Fluorescent Proteins; HEK293 Cells; Humans; Infant; Intracellular Signaling Peptides and Proteins; Male; Mice; Mice, Transgenic; Movement Disorders; Myelin Basic Protein; Myelin Sheath; Neurodegenerative Diseases; Oligodendroglia

Glatiramer acetate (GA; Copaxone) is an approved drug for the treatment of multiple sclerosis (MS). The underlying multifactorial anti-inflammatory, neuroprotective effect of GA is in the induction of reactive T cells that release immunomodulatory cytokines and neurotrophic factors at the injury site. These GA-induced cytokines and growth factors may have a direct effect on axon function. Building on previous findings that suggest a neuroprotective effect of GA, we assessed the therapeutic effects of GA on brain and spinal cord pathology and functional correlates using the chronic experimental autoimmune encephalomyelitis (EAE) mouse model of MS. Therapeutic regimens were utilized based on promising prophylactic efficacy. More specifically, C57BL/6 mice were treated with 2 mg/mouse/day GA for 8 days beginning at various time points after EAE post-induction day 15, yielding a thorough, clinically relevant assessment of GA efficacy within the context of severe progressive disease. Therapeutic treatment with GA significantly decreased clinical scores and improved rotorod motor performance in EAE mice. These functional improvements were supported by an increase in myelinated axons and fewer amyloid precursor protein-positive axons in the spinal cords of GA-treated EAE mice. Furthermore, therapeutic GA decreased microglia/macrophage and T cell infiltrates and increased oligodendrocyte numbers in both the spinal cord and corpus callosum of EAE mice. Finally, GA improved callosal axon conduction and nodal protein organization in EAE. Our results demonstrate that therapeutic GA treatment has significant beneficial effects in a chronic mouse model of MS, in which its positive effects on both myelinated and non-myelinated axons results in improved axon function.

Topics: Action Potentials; Animals; Axons; Basic Helix-Loop-Helix Transcription Factors; Brain; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Glatiramer Acetate; Immunosuppressive Agents; In Vitro Techniques; Mice; Mice, Inbred C57BL; Mice, Transgenic; Movement Disorders; Myelin Basic Protein; Myelin Proteolipid Protein; Nerve Tissue Proteins; Neural Conduction; Oligodendrocyte Transcription Factor 2; Oligodendroglia; Peptides; Severity of Illness Index; Spinal Cord; Time Factors

Trophic support and myelination of axons by Schwann cells in the PNS are essential for normal nerve function. Herein, we show that deletion of the LDL receptor-related protein-1 (LRP1) gene in Schwann cells (scLRP1(-/-)) induces abnormalities in axon myelination and in ensheathment of axons by nonmyelinating Schwann cells in Remak bundles. These anatomical changes in the PNS were associated with mechanical allodynia, even in the absence of nerve injury. In response to crush injury, sciatic nerves in scLRP1(-/-) mice showed accelerated degeneration and Schwann cell death. Remyelinated axons were evident 20 d after crush injury in control mice, yet were largely absent in scLRP1(-/-) mice. In the partial nerve ligation model, scLRP1(-/-) mice demonstrated significantly increased and sustained mechanical allodynia and loss of motor function. Evidence for central sensitization in pain processing included increased p38MAPK activation and activation of microglia in the spinal cord. These studies identify LRP1 as an essential mediator of normal Schwann cell-axonal interactions and as a pivotal regulator of the Schwann cell response to PNS injury in vivo. Mice in which LRP1 is deficient in Schwann cells represent a model for studying how abnormalities in Schwann cell physiology may facilitate and sustain chronic pain.

Topics: Actins; Analysis of Variance; Animals; Axons; CD11b Antigen; Cytoplasm; Disease Models, Animal; Gene Expression Regulation; Hyperalgesia; In Situ Nick-End Labeling; Indoles; Low Density Lipoprotein Receptor-Related Protein-1; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Electron, Transmission; Movement Disorders; Myelin Basic Protein; Nerve Degeneration; p38 Mitogen-Activated Protein Kinases; Pain Measurement; Phosphorylation; Posterior Horn Cells; Receptors, LDL; S100 Proteins; Schwann Cells; Sciatica; Sensation Disorders; Spinal Cord; Tumor Suppressor Proteins

p23 belongs to the highly conserved p24 family of type I transmembrane proteins, which participate in the bidirectional protein transport between the endoplasmic reticulum and Golgi apparatus. Mammalian p23 has been shown to interact with γ-secretase complex, and modulate secretory trafficking as well as intramembranous processing of amyloid precursor protein in cultured cells. Negative modulation of β-amyloid production by p23 in cultured cell lines suggested that elevation of p23 expression in neurons might mitigate cerebral amyloid burden.. We generated several lines of transgenic mice expressing human p23 in neurons under the control of Thy-1.2 promoter. We found that even a 50% increase in p23 levels in the central nervous system of mice causes post-natal growth retardation, severe neurological problems characterized by tremors, seizure, ataxia, and uncoordinated movements, and premature death. The severity of the phenotype closely correlated with the level of p23 overexpression in multiple transgenic lines. While the number and general morphology of neurons in Hup23 mice appeared to be normal throughout the brain, abnormal non-Golgi p23 localization was observed in a subset of neurons with high transgene expression in brainstem. Moreover, detailed immunofluorescence analysis revealed marked proliferation of astrocytes, activation of microglia, and thinning of myelinated bundles in brainstem of Hup23 mice.. These results demonstrate that proper level of p23 expression is critical for neuronal function, and perturbing p23 function by overexpression initiates a cascade of cellular reactions in brainstem that leads to severe motor deficits and other neurological problems, which culminate in premature death. The neurological phenotype observed in Hup23 mice highlights significant adverse effects associated with manipulating neuronal expression of p23, a previously described negative modulator of γ-secretase activity and β-amyloid production. Moreover, our report has broader relevance to molecular mechanisms in several neurodegenerative diseases as it highlights the inherent vulnerability of the early secretory pathway mechanisms that ensure proteostasis in neurons.

Topics: Amyloid beta-Protein Precursor; Animals; Brain; Cells, Cultured; Humans; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Movement Disorders; Myelin Basic Protein; Neurons; Nucleocytoplasmic Transport Proteins

Glutamate excitotoxicity plays a role in white matter injury in many neurological diseases. Oligodendrocytes in particular are highly vulnerable to excitotoxicity, mediated through activation of AMPA/kainate receptors. Myelin may also be injured independently via NMDA (N-methyl-D-aspartic acid) receptors located on peripheral oligodendroglial processes. Central axons are susceptible to glutamate receptor activation in vivo, but it is unclear whether this is mediated directly by activation of receptors expressed on axons, or indirectly through glutamate toxicity of myelin or neighboring glial cells. We examined axonal vulnerability in mice deficient in myelin basic protein (shiverer), also expressing yellow fluorescent protein (YFP) in a subset of axons. YFP fluorescence, EM, and mouse behavior were assessed 24 h after microstereotactical injections of S-AMPA or NMDA into lumbar dorsal columns. S-AMPA injection led to impaired rotarod performance and widespread axonal degeneration and was more pronounced in shiverer mice than controls. In contrast, NMDA injection did not cause axonal injury or behavioral changes in either group. These results indicate that spinal cord axons in vivo are vulnerable to toxicity mediated by AMPA but not NMDA receptors. The presence of compact myelin is not required for excitotoxic axon damage, and its absence may increase vulnerability. Further understanding of AMPA receptor-mediated axonal toxicity may provide new targets for neuroprotective therapy in WM diseases.

Topics: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Animals; Biomarkers; Brain; Disease Models, Animal; Excitatory Amino Acid Agonists; Female; Hereditary Central Nervous System Demyelinating Diseases; Luminescent Proteins; Mice; Mice, Inbred C57BL; Mice, Neurologic Mutants; Movement Disorders; Myelin Basic Protein; N-Methylaspartate; Nerve Degeneration; Nerve Fibers, Myelinated; Neurotoxins; Receptors, AMPA

Our previous study showed that treatment with alpha-phenyl-n-tert-butyl-nitrone (PBN) after exposure to lipopolysaccharide (LPS) reduced LPS-induced white matter injury in the neonatal rat brain. The object of the current study was to further examine whether PBN has long-lasting protective effects and ameliorates LPS-induced neurological dysfunction. Intracerebral (i.c.) injection of LPS (1 mg/kg) was performed in postnatal day (P) 5 Sprague Dawley rat pups and PBN (100 mg/kg) or saline was administered intraperitoneally 5 min after LPS injection. The control rats were injected (i.c.) with sterile saline. Neurobehavioral tests were carried out from P3 to P21, and brain injury was examined after these tests. LPS exposure resulted in severe brain damage, including enlargement of ventricles bilaterally, loss of mature oligodendrocytes, impaired myelination as indicated by the decrease in myelin basic protein immunostaining, and alterations in dendritic processes in the cortical gray matter of the parietal cortex. Electron microscopic examination showed that LPS exposure caused impaired myelination as indicated by the disintegrated myelin sheaths in the juvenile rat brain. LPS administration also significantly affected neurobehavioral functions such as performance in righting reflex, wire hanging maneuver, cliff avoidance, negative geotaxis, vibrissa-elicited forelimb-placing test, beam walking, and gait test. Treatment with PBN, a free radical scavenger and antioxidant, provided protection against LPS-induced brain injury and associated neurological dysfunction in juvenile rats, suggesting that antioxidation might be an effective approach for therapeutic treatment of neonatal brain injury induced by infection/inflammation.

Topics: Animals; Animals, Newborn; Brain; Brain Damage, Chronic; Central Nervous System Bacterial Infections; Cyclic N-Oxides; Disease Models, Animal; Female; Gait Disorders, Neurologic; Humans; Infant, Newborn; Infectious Disease Transmission, Vertical; Leukomalacia, Periventricular; Lipopolysaccharides; Male; Movement Disorders; Myelin Basic Protein; Nerve Fibers, Myelinated; Neuroprotective Agents; Oligodendroglia; Pregnancy; Rats; Rats, Sprague-Dawley; Recovery of Function; Reflex