Simple and Computer-assisted Olfactory Testing for Mice

Olfaction is highly conserved among species and is required for reproduction and survival.
In humans, olfaction is also one of the senses that is affected ...

An Alternative Approach to Study Primary Events in Neurodegeneration Using <em>Ex Vivo</em> Rat Brain Slices

Despite&#160;numerous studies that attempt to develop reliable animal models&#160;which reflecting the primary processes underlying neurodegeneration, ...

University of Fribourg

Culham Science Centre

Notch signaling is an evolutionarily conserved pathway, which is fundamental for neuronal development and specification. In the last decade, increasing evidence has pointed out an important role of this pathway beyond embryonic development, indicating that Notch also displays a critical function in the mature brain of vertebrates and invertebrates. This pathway appears to be involved in neural progenitor regulation, neuronal connectivity, synaptic plasticity and learning/memory. In addition, Notch appears to be aberrantly regulated in neurodegenerative diseases, including Alzheimer's disease and ischemic injury. The molecular mechanisms by which Notch displays these functions in the mature brain are not fully understood, but are currently the subject of intense research. In this review, we will discuss old and novel Notch targets and molecular mediators that contribute to Notch function in the mature brain and will summarize recent findings that explore the two facets of Notch signaling in brain physiology and pathology.

Notch signaling in the brain: in good and bad times.

The function of the nuclear receptor Rev-erbα (Nr1d1) in the brain is, apart from its role in the circadian clock mechanism, unknown. Therefore, we compared gene expression profiles in the brain between wild-type and Rev-erbα knock-out (KO) animals. We identified fatty acid binding protein 7 (Fabp7, Blbp) as a direct target of repression by REV-ERBα. Loss of Rev-erbα manifested in memory and mood related behavioral phenotypes and led to overexpression of Fabp7 in various brain areas including the subgranular zone (SGZ) of the hippocampus, where neuronal progenitor cells (NPCs) can initiate adult neurogenesis. We found increased proliferation of hippocampal neurons and loss of its diurnal pattern in Rev-erbα KO mice. In vitro, proliferation and migration of glioblastoma cells were affected by manipulating either Fabp7 expression or REV-ERBα activity. These results suggest an important role of Rev-erbα and Fabp7 in adult neurogenesis, which may open new avenues for treatment of gliomas as well as neurological diseases such as depression and Alzheimer.

The nuclear receptor REV-ERBα regulates Fabp7 and modulates adult hippocampal neurogenesis.

Notch signalling plays an important role in synaptic plasticity, learning and memory functions in both Drosophila and rodents. In this paper, we report that this feature is not restricted to hippocampal networks but also involves the olfactory bulb (OB). Odour discrimination and olfactory learning in rodents are essential for survival. Notch1 expression is enriched in mitral cells of the mouse OB. These principal neurons are responsive to specific input odorants and relay the signal to the olfactory cortex. Olfactory stimulation activates a subset of mitral cells, which show an increase in Notch activity. In Notch1cKOKln mice, the loss of Notch1 in mitral cells affects the magnitude of the neuronal response to olfactory stimuli. In addition, Notch1cKOKln mice display reduced olfactory aversion to propionic acid as compared to wildtype controls. This indicates, for the first time, that Notch1 is involved in olfactory processing and may contribute to olfactory behaviour.

Notch1 activity in the olfactory bulb is odour-dependent and contributes to olfactory behaviour.

Currently there is no widely accepted animal model reproducing the full pathological profile of Alzheimer's disease (AD), since the basic mechanisms of neurodegeneration are still poorly understood. We have proposed that the interaction between the α7 nicotinic acetylcholine receptor (α7-nAChR) and a recently discovered toxic peptide, cleaved from the acetylcholinesterase (AChE) C-terminus, could account for the aberrant processes occurring in AD. In this article we describe a new application onmodel procedure, which combines the advantages of bothandpreparations, to study the effects of the AChE-derived peptide on the rat basal forebrain (BF). Western blot analysis showed that the levels of α7-nAChR, p-Tau and Aβ are differentially expressed upon the AChE-peptide administration, in a selective site-dependent manner. In conclusion, this methodology demonstrates the action of a novel peptide in triggering an AD-like phenotype and proposes a newapproach for manipulating and monitoring neurochemical processes contributing to neurodegeneration, in a time-dependent and site-specific manner.

Emanuele Brai

Unit of Anatomy,
Department of Medicine,
Unit of Anatomy, Department of Medicine

University of Fribourg

Simple and Computer-assisted Olfactory Testing for Mice

An Alternative Approach to Study Primary Events in Neurodegeneration Using Ex Vivo Rat Brain Slices

Emanuele Brai

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Unit of Anatomy,Department of Medicine,Unit of Anatomy, Department of Medicine

University of Fribourg

Simple and Computer-assisted Olfactory Testing for Mice

An Alternative Approach to Study Primary Events in Neurodegeneration Using Ex Vivo Rat Brain Slices

Unit of Anatomy,
Department of Medicine,
Unit of Anatomy, Department of Medicine