Pattern of Notch2, Numb, and Cas8 Gene Expression in Relevant Structures of the Rat Brain during Formation of Spatial Memory

Analysis of the Dynamics of Cognitive Impairments and Expression of Caspase Cascade Genes in Preclinical Stages of Parkinsonism Modeled Using α-Synuclein Oligomers

The behavioral effects of α-synuclein oligomers were studied at various times after its chronic intranasal administration to 75-day-old C57BL/6J mice in comparison with the dynamics of changes in the transcriptional activity of caspases genes (Casp9, Casp8, and Casp3) in the hippocampus, frontal cortex, and cerebellum. The negative effects of α-synuclein oligomers on exploratory activity and short-term memory in the novel object recognition test were most pronounced after 90 days from the end of administration, while after 1 and 270 days, partial compensation of the studied cognitive functions was observed. Analysis of the expression of caspase genes suggests that early compensatory mechanisms are associated with suppression of the effector caspase-3 gene expression along with increased activity of the genes encoding initiator caspases-9 and -8. Late compensation processes are associated with a decrease in the activity of initiator caspases in the frontal cortex and cerebellum.

Analysis of NAPA Gene Expression in Brain Structures of Wistar Rats during the Formation of Long-Term Spatial Memory and Physical Activity under Stress Situation

In the cerebellum, hippocampus, and prefrontal cortex of mature male Wistar rats with trained spatial navigational skill in the Morris water maze, the transcriptional activity the NAPA gene that regulates the transport and secretion of synaptic vesicles, release of neurotransmitters, and protein degradation was determined by real-time PCR. Animals subjected to forced swimming in a time-matched regime (active control) and naïve rats were used as the comparison groups. Suppression of NAPA gene activity was found in the hippocampus and cerebellum of the active control group, while navigation skill training led to a significant increase in gene expression in all brain structures under study. The findings suggest the existence of specific mechanisms regulating NAPA gene activity during the formation of spatial memory and adaptive behavior under stress conditions.

Cerebral Expression of the Neuregulin-1 Gene NRG1 during Induced Spatial Memory Impairment and Its Reversal in Aging Mice

We studied the effects of chronic intranasal administration of amyloidogenic fibrils of the proinflammatory protein S100A9 alone or in combination with glutamate antibodies on the expression of the neuregulin-1 gene (NRG1), a regulator of various physiological processes, in particular, regulation of neurogenesis and apoptosis, in the hippocampus, prefrontal cortex, and cerebellum of aging C57BL/6 mice under conditions of long-term memory disturbances. Under conditions of amnesia induced by S100A9 fibrils, pronounced (>90%) blockade of the expression of the NRG1 gene was found in all cerebral structures. Glutamate antibodies prevented/corrected disturbances in the cerebral expression of the NRG1 gene, thereby maintaining the activity of the NRG1/ErbB molecular signaling system, probably associated with the formation of spatial memory.

Effects of Antibodies to Glutamate on Cerebral Expression of the Tnfrsf1A Gene under Conditions of Spatial Amnesia Induced by Proinflammatory Protein S100A9 Fibrils in Aging Mice

Proinflammatory S100A9 protein is a promoter of inflammation-linked neurodegeneration and the Tnfrsf1A gene encodes the TNF receptor 1A that binds TNFα to function as a regulator of inflammation. We studied the effects of chronic intranasal administration of in vitro prepared S100A9 fibrils alone or in combination with anti-glutamate antibodies on the expression of the Tnfrsf1A gene in the hippocampus, prefrontal cortex, and cerebellum of aging C57BL/6 mice under conditions of impaired spatial memory. A differential cerebral pattern of Tnfrsf1A gene activity and its modification by S100A9 fibrillar structures were observed: inhibition of Tnfrsf1A gene expression in the hippocampus and cerebellum and its activation in the prefrontal cortex. Anti-glutamate antibodies normalized the expression of the Tnfrsf1A gene in the prefrontal cortex by affecting the TNF signaling pathway and preventing the development of inflammation.

Post-Developmental Roles of Notch Signaling in the Nervous System

Since its discovery in Drosophila, the Notch signaling pathway has been studied in numerous developmental contexts in diverse multicellular organisms. The role of Notch signaling in nervous system development has been extensively investigated by numerous scientists, partially because many of the core Notch signaling components were initially identified through their dramatic ‘neurogenic’ phenotype of developing fruit fly embryos. Components of the Notch signaling pathway continue to be expressed in mature neurons and glia cells, which is suggestive of a role in the post-developmental nervous system. The Notch pathway has been, so far, implicated in learning and memory, social behavior, addiction, and other complex behaviors using genetic model organisms including Drosophila and mice. Additionally, Notch signaling has been shown to play a modulatory role in several neurodegenerative disease model animals and in mediating neural toxicity of several environmental factors. In this paper, we summarize the knowledge pertaining to the post-developmental roles of Notch signaling in the nervous system with a focus on discoveries made using the fruit fly as a model system as well as relevant studies in C elegans, mouse, rat, and cellular models. Since components of this pathway have been implicated in the pathogenesis of numerous psychiatric and neurodegenerative disorders in human, understanding the role of Notch signaling in the mature brain using model organisms will likely provide novel insights into the mechanisms underlying these diseases.