title: Neurodegeneration in Autoimmune Optic Neuritis Is Associated with Altered APP Cleavage in Neurons and Up-Regulation of p53.
abstract: Multiple Sclerosis (MS) is a chronic autoimmune inflammatory disease of the central nervous system (CNS). Histopathological and radiological analysis revealed that neurodegeneration occurs early in the disease course. However, the pathological mechanisms involved in neurodegeneration are poorly understood. Myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) in Brown Norway rats (BN-rats) is a well-established animal model, especially of the neurodegenerative aspects of MS. Previous studies in this animal model indicated that loss of retinal ganglion cells (RGCs), the neurons that form the axons of the optic nerve, occurs in the preclinical phase of the disease and is in part independent of overt histopathological changes of the optic nerve. Therefore, the aim of this study was to identify genes which are involved in neuronal cell loss at different disease stages of EAE. Furthermore, genes that are highly specific for autoimmune-driven neurodegeneration were compared to those regulated in RGCs after optic nerve axotomy at corresponding time points. Using laser capture micro dissection we isolated RNA from unfixed RGCs and performed global transcriptome analysis of retinal neurons. In total, we detected 582 genes sequentially expressed in the preclinical phase and 1150 genes in the clinical manifest EAE (P < 0.05, fold-induction >1.5). Furthermore, using ingenuity pathway analysis (IPA), we identified amyloid precursor protein (APP) as a potential upstream regulator of changes in gene expression in the preclinical EAE but neither in clinical EAE, nor at any time point after optic nerve transection. Therefore, the gene pathway analysis lead to the hypothesis that altered cleavage of APP in neurons in the preclinical phase of EAE leads to the enhanced production of APP intracellular domain (AICD), which in turn acts as a transcriptional regulator and thereby initiates an apoptotic signaling cascade via up-regulation of the target gene p53.
authors.affiliation: Department of Neurology, University Medicine Göttingen, Göttingen, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Herold
authors.affiliation: Department of Neurology, University Medicine Göttingen, Göttingen, Germany.
authors.forename: Prateek
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Molecular and Behavioral Neurobiology, Department of Psychiatry, Ludwig Maximilians University Munich, Munich, Germany.
authors.forename: Sven P
authors.initials: SP
authors.lastname: Wichert
authors.affiliation: Department of Neurology, University Medicine Göttingen, Göttingen, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Kretzschmar
authors.affiliation: Department of Neurology, University Medicine Göttingen, Göttingen, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Bähr
authors.affiliation: Molecular and Behavioral Neurobiology, Department of Psychiatry, Ludwig Maximilians University Munich, Munich, Germany.
authors.forename: Moritz J
authors.initials: MJ
authors.lastname: Rossner
authors.affiliation: Department of Neurology, University Medicine Göttingen, Göttingen, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Hein
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000150:complications*; D005260:Female; D020411:Oligonucleotide Array Sequence Analysis; D009900:Optic Nerve / Q000378:metabolism / Q000473:pathology; D009902:Optic Neuritis / Q000150:complications / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D059748:Proteolysis; D051381:Rats; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*; D015854:Up-Regulation
chemical_list: D016564:Amyloid beta-Protein Precursor; D016159:Tumor Suppressor Protein p53