Scientific Report 2003-2004 - Cleveland Clinic Lerner Research ...

Amyotrophic lateral sclerosis (ALS, LouGehrig’s disease) is probably the mostdreaded of neurodegenerative diseases.There is no cure for this disorder, which causesprogressive paralysis, muscle atrophy, and death,usually from respiratory complications. In theUnited States, it occurs as frequently as multiplesclerosis, with over 5,000 new cases occurring peryear. However, only about 30,000patients are living, becausesurvival averages three to fiveyears after symptom onset.The cause of ALS isunknown, and clinical diagnosis isusually difficult, especially in earlystages. My studies focus on twoseparate but complementary linesof research, which address theseissues.• Molecular mechanismsof motor neuron degeneration arestudied in the spontaneous mutantwobbler mouse and transgenicmouse that overexpresses amutant human Cu,Zn-superoxidedismutase (mH-SOD1) gene.Experimental therapies aimed atblocking these mechanisms aretested for rescuing their phenotypes.• Neuroimaging techniquesof magnetic resonance imaging (MRI) andproton magnetic resonance spectroscopy ( 1 H-MRS) are used to identify motor pathwayabnormalities in the brains of patients with ALSand the mouse models; postmortem studies revealthe histopathologic correlates.The wobbler mouse and mH-SOD1transgenic mouse provide excellent substrates toinvestigate the pathogenic mechanisms of motorneuron degeneration in ALS, including oxidativestress, excitotoxicity, mitochondrial dysfunction,and aggregation of ubiquitinated proteins. Workin the laboratory focuses on examining thesignificance of ubiquitinated aggregates,intermediate filament accumulation, andmitochondrial dysfunction in wobbler motorneurons. Based on these findings, we testtherapies that prevent these abnormalities andpotentially rescue the phenotype, includingpharmacologic treatments and cross-breedingwobbler mice with mice transgenic for specificgenes.We are examining whether abnormalities inthe ATP-dependent ubiquitin-proteasome systemof wobbler cervical spinal cord motor neuronsThe Department of NeurosciencesImaging, Molecular Mechanism StudiesAim to Identify Causes of ALScause inadequate proteolysis and intraneuronalaccumulation of proteins. This condition wouldbe detrimental to cellular functioning and wouldlikely contribute to neurodegeneration. Ourstudies compare the mH-SOD1 mouse and humanALS spinal cord tissue to determine if relatedabnormalities occur (e.g., in mitochondria) and ifa ubiquitinated protein can be characterized inALS tissue. We are alsocharacterizing mitochondrialabnormalities in the brain andcervical spinal cord ofwobbler mice, which probablyresult in deficient ATPproduction.In vivo MR imaging ofbrain and spinal cord inpatients with ALS revealsevidence of motor neuronand motor pathway (corticospinaltract) degeneration.We have demonstrated thiswith 1 H-MRS and moretraditional MRI. There isneurochemical evidence from1H-MRS of glutamateglutamineexcess in brainstemregions, which correlates withbulbar (speech and swallowing)dysfunction, supportingErik P. Pioro, M.D., Ph.D.an excitotoxic pathogenicmechanism. Similar 1 H-MRSchanges in the wobbler mouse brain in vivo,confirmed by immunohistochemistry, revealfurther similarities with ALS. Correlative MRIand histopathologic studies of brain from ALSpatients and mouse models are providingsignificant insights into the evolution andmechanisms of motor neuron degeneration.THE PIOROLABORATORYINVESTIGATORSVladymyr Kostenko, M.D.Jialin Zhang, M.D.COLLABORATORSMichael Coleman, Ph.D. 1Douglas A. Gray, Ph.D. 2Andrei Gudkov, Ph.D. 3Michael T. Kinter, Ph.D. 4Michael Phillips, M.D. 5Dennis J. Stuehr, Ph.D. 6Scott M. Wilson, Ph.D. 71Cologne, Germany2Ottawa Health Research Inst.,Ottawa, Ont., Canada3Dept. of Molecular Biology,CCF4Dept. of Cell Biology, CCF5Dept. of Neuroradiology, CCF6Dept. of Immunology, CCF7Dept. of Neurobiology, Univ.of Alabama at BirminghamPioro, E.P., Wang, Y., Moore, J.K., Ng, T.C., Trapp, B.D., Klinkosz, B., and H. Mitsumoto(1998) Neuronal pathology in the wobbler mouse brain revealed by in vivo protonmagnetic resonance spectroscopy and immunocytochemistry. NeuroReport9:3041-3046.Pioro, E.P., Majors, A.W., Mitsumoto, H., Nelson, D.R., and T.C. Ng (1999) 1 H-MRSevidence of neurodegeneration and excess glutamate+glutamine in ALS medulla. Neurology53:71-79.Tsuzaka, K., Ishiyama, T., Pioro, E.P., and H. Mitsumoto (2001) Role of brain-derivedneurotrophic factor in wobbler mouse motor neuron disease. Muscle Nerve 24:474-480.Mitsumoto, H., Klinkosz, B., Pioro, E.P., Tsuzaka, K., Ishiyama, T., O’Leary, R.M.,and D. Pennica (2001) Effects of cardiotrophin-1 (CT-1) in a mouse motor neuron disease.Muscle Nerve 24:769-777.Dal Bello-Haas, V., Andrews-Hinders, D., Richer, C.B., Blakely-Adams, C., Hanson,J., Hammel, J., Kelly, D., Kloos, A., Pioro, E.P., Powazki, R.D., Wheeler, T., and H.Mitsumoto (2001) Development, analysis, refinement, and utility of an interdisciplinaryamyotrophic lateral sclerosis database. Amyotroph. Lateral Scler. Other MotorNeuron Disord. 2:39-46.145