Glial Amyloid Precursor Protein Expression is Restricted to Astrocytes in an Experimental Toxic Model of Multiple Sclerosis Tim Clarner & Jan Philipp Buschmann & Cordian Beyer & Markus Kipp Received: 26 May 2010 / Accepted: 22 June 2010 / Published online: 7 July 2010 # Springer Science+Business Media, LLC 2010 Abstract The amyloid precursor protein is rapidly induced in reactive glia in response to pathological stimuli and inflammation. In this study, we investigated its expression in an experimental multiple sclerosis animal model, the cuprizone mouse model which reveals massive myelin loss. Cuprizone intoxication for 5 weeks induced immense demyelination of the corpus callosum and resulted in hypertrophic and hyperplastic astrocytosis accompanied by microglia/macrophage invasion. Using double- immunofluorescence, real-time quantitative PCR and West- ern Blot, we observed that activated astrocytes are the main source of amyloid precursor protein during demyelination. In order to rule out astrocytes, in general, responding to inflammatory and toxic compounds by amyloid precursor protein expression, neonatal astroglia cultures were exposed to various stimuli. Under control conditions, astroglial amyloid precursor protein was only moderately expressed. None of the treatments had a significant effect on its expression in vitro. Our results suggest that amyloid precursor protein is specifically up-regulated under cuprizone-induced demyelination. It remains to be further elucidated whether amyloid precursor protein-positive astrocytes are directly implicated in the pathological mechanism of demyelination. Keywords Amyloid precursor protein . Astroglia . Microglia . Cuprizone . Demyelination Abbreviations AD Alzheimers disease APP Amyloid precursor protein CC Corpus callosum cDNA Complementary DNA Cu Cuprizone EAE Experimental Autoimmune Encephalitis GFAP Glial fibrillary acidic protein H 2 O 2 Hydrogen peroxide HPRT Hypoxanthine guanine phosphoribosyltransferase Iba1 Ionized calcium-binding adaptor molecule 1 M-MLV Moloney Murine Leukemia Virus MS Multiple sclerosis OD Optical density PLB-TCEP Protein loading buffer Tris (2-carbox- yethyl)phosphine Hydrochloride PLP Proteolipid protein Real-time RT- PCR Real-time reverse transcriptase quantitative polymerase chain reaction SDS-PAGE Sodium dodecylsulfate polyacrylamide gel electrophoresis SEM Standard error of the mean TAQ Polymer- ase Thermus aquaticus DNA polymerase T. Clarner : J. Buschmann : C. Beyer : M. Kipp (*) Institute of Neuroanatomy, Faculty of Medicine, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany e-mail: mkipp@ukaachen.de J Mol Neurosci (2011) 43:268–274 DOI 10.1007/s12031-010-9419-9