title: Neurons generated from APP/APLP1/APLP2 triple knockout embryonic stem cells behave normally in vitro and in vivo: lack of evidence for a cell autonomous role of the amyloid precursor protein in neuronal differentiation.
abstract: Alzheimer's disease amyloid precursor protein (APP) has been implicated in many neurobiologic processes, but supporting evidence remains indirect. Studies are confounded by the existence of two partially redundant APP homologues, APLP1 and APLP2. APP/APLP1/APLP2 triple knockout (APP tKO) mice display cobblestone lissencephaly and are perinatally lethal. To circumvent this problem, we generated APP triple knockout embryonic stem (ES) cells and differentiated these to APP triple knockout neurons in vitro and in vivo. In comparison with wild-type (WT) ES cell-derived neurons, APP tKO neurons formed equally pure neuronal cultures, had unaltered in vitro migratory capacities, had a similar acquisition of polarity, and were capable of extending long neurites and forming active excitatory synapses. These data were confirmed in vivo in chimeric mice with APP tKO neurons expressing the enhanced green fluorescent protein (eGFP) present in a WT background brain. The results suggest that the loss of the APP family of proteins has no major effect on these critical neuronal processes and that the apparent multitude of functions in which APP has been implicated might be characterized by molecular redundancy. Our stem cell culture provides an excellent tool to circumvent the problem of lack of viability of APP/APLP triple knockout mice and will help to explore the function of this intriguing protein further in vitro and in vivo.
authors.affiliation: Laboratory of Neuronal Cell Biology and Gene Transfer, Leuven, Belgium.
authors.forename: Bruno A
authors.initials: BA
authors.lastname: Bergmans
authors.forename: S Ali M
authors.initials: SA
authors.lastname: Shariati
authors.forename: Ron L P
authors.initials: RL
authors.lastname: Habets
authors.forename: Patrik
authors.initials: P
authors.lastname: Verstreken
authors.forename: Luc
authors.initials: L
authors.lastname: Schoonjans
authors.forename: Ulrike
authors.initials: U
authors.lastname: Müller
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Dotti
authors.forename: Bart
authors.initials: B
authors.lastname: De Strooper
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000235:genetics*; D000818:Animals; D001921:Brain / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement / Q000235:genetics; D016764:Cell Polarity / Q000235:genetics; D002478:Cells, Cultured; D002678:Chimera; D054222:Cobblestone Lissencephaly / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009421:Nervous System Malformations / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D009434:Neural Pathways / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D016501:Neurites / Q000378:metabolism / Q000648:ultrastructure; D055495:Neurogenesis / Q000235:genetics*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*
chemical_list: D016564:Amyloid beta-Protein Precursor; C078201:Aplp1 protein, mouse; C492952:Aplp2 protein, mouse; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins