Proteomic Characterization of a Mouse Model of Familial Danish Dementia.

A dominant mutation in the ITM2B/BRI2 gene causes familial Danish dementia (FDD) in humans. To model FDD in animal systems, a knock-in approach was recently implemented in mice expressing a wild-type and mutant allele, which bears the FDD-associated mutation. Since these FDD_KI mice show behavioural alterations and impaired synaptic function, we characterized their synaptosomal proteome via two-dimensional differential in-gel electrophoresis. After identification by nanoliquid chromatography coupled to electrospray-linear ion trap tandem mass spectrometry, the differentially expressed proteins were classified according to their gene ontology descriptions and their predicted functional interactions. The Dlg4/Psd95 scaffold protein and additional signalling proteins, including protein phosphatases, were revealed by STRING analysis as potential players in the altered synaptic function of FDD_KI mice. Immunoblotting analysis finally demonstrated the actual downregulation of the synaptosomal scaffold protein Dlg4/Psd95 and of the dual-specificity phosphatase Dusp3 in the synaptosomes of FDD_KI mice. [ABSTRACT FROM AUTHOR]