Early and sustained altered expression of aging-related genes in young 3xTg-AD mice

Alzheimer's disease (AD) is a multifactorial neurological condition associated with a genetic profile that is still not completely understood. In this study, using a whole gene microarray approach, we investigated age-dependent gene expression profile changes occurring in the hippocampus of young and old transgenic AD (3xTg-AD) and wild-type (WT) mice. The aim of the study was to assess similarities between aging- and AD-related modifications of gene expression and investigate possible interactions between the two processes. Global gene expression profiles of hippocampal tissue obtained from 3xTg-AD and WT mice at 3 and 12 months of age (m.o.a.) were analyzed by hierarchical clustering. Interaction among transcripts was then studied with the Ingenuity Pathway Analysis (IPA) software, a tool that discloses functional networks and/or pathways associated with sets of specific genes of interest. Cluster analysis revealed the selective presence of hundreds of upregulated and downregulated transcripts. Functional analysis showed transcript involvement mainly in neuronal death and autophagy, mitochondrial functioning, intracellular calcium homeostasis, inflammatory response, dendritic spine formation, modulation of synaptic functioning, and cognitive decline. Thus, overexpression of AD-related genes (such as mutant APP, PS1, and hyperphosphorylated tau, the three genes that characterize our model) appears to favor modifications of additional genes that are involved in AD development and progression. The study also showed overlapping changes in 3xTg-AD at 3 m.o.a. and WT mice at 12 m.o.a., thereby suggesting altered expression of aging-related genes that occurs earlier in 3xTg-AD mice

Principles driving the spatial organization of Rho GTPase signaling at synapses

The Rho proteins play critical roles in numerous aspects of neuronal development, and mutations in their regulators (GEFs and GAPs) and effectors underlie multiple neurodevelopmental and neurological disorders. How Rho GTPase-mediated signaling can have a hand in regulating so many different neurobiological processes remains a challenging question. An emerging theme is that GAPs and GEFs, through their spatial/temporal regulation and/or through additional protein-protein interactions, cooperate in making connections between upstream signals and the downstream signaling output, engaging distinct effector proteins. This chapter focuses on recent evidence illustrating distinct modes of regulation and specialized roles of Rho regulators particularly in the context of synaptic structure, function, and plasticity, and how their dysregulation affects behavioral processes and contributes to disease. © 2014 Springer-Verlag Wien. All rights reserved