Project description:Aging is associated with a decline in hippocampal mediated learning and memory, a process which can be ameliorated by dietary (caloric) restriction. We used Affymetrix gene expression analysis to monitor changes in three regions of the hippocampus (CA1, CA3, DG) of middle aged (18 months) and old (28 month) rats that were exposed to dietary restriction. Old rats were determined to be good performers (GP) or poor performers (PP) in behavioural tests to assess their hippocampal function. We used Affymetrix gene expression analysis to monitor changes in three regions of the hippocampus (CA1, CA3, DG) of middle aged (18 months) and old (28 month) rats that were exposed to dietary restriction.
Project description:The project examined age-related change in hippocampal gene expression in Fisher 344 x Brown Norway F1 rats from the NIA aging colony (Adult = 12M, Aged = 24M). CA1, CA3, and DG specific dissections were examined from one cohort of animals and from a second cohort whole hippocampus was used. Hippocampal gene expression with aging in a rat model was examined between Adult (12M) and Aged animals (24M)
Project description:Aging is associated with a decline in hippocampal mediated learning and memory, a process wich can be ameliorated by dietary (caloric) restriction. We used Affymetrix gene expression analysis to monitor changes in three regions of the hippocampus (CA1, CA3, DG) of middle aged (18 months) and old (28 month) rats that were exposed to dietary restriction. Old rats were determined to be good performers (GP) or poor performers (PP) in behavioral tests to assess thier hippocampal function.
Project description:Purpose: In this study, we used LCM and RNA-Seq to characterize differences in the rat hippocampal expression profiles of CA1, CA2, CA3, and DG subfields Methods: Each subfield was bilaterally laser microdissected, collected from the rat's hippocampus (n=4), and submitted to Illuminas for massively parallel sequencing. Results: We found evident segregation of the transcriptomic profile from different regions of the hippocampus. Gene ontology enrichment analysis of CA1 subfield results in actin regulation genes and postsynaptic membrane AMPA receptors that are indispensable for long-term potentiation and learning and memory. CA2 and CA3 transcripts were found associated with the higher metabolic processes. DG expression was enriched for ribosome and spliceosome, both required for protein synthesis and maintenance of cell life. Conclusion: The present findings contribute to a deeper understanding of the differences in the molecular machinery expressed by the rat hippocampal neuronal populations, further exploring underlying mechanisms responsible for each subflied specific functions.
Project description:The project examined age-related change in hippocampal gene expression in Fisher 344 x Brown Norway F1 rats from the NIA aging colony (Adult = 12M, Aged = 24M). CA1, CA3, and DG specific dissections were examined from one cohort of animals and from a second cohort whole hippocampus was used.
Project description:We have previously demonstrated functional and molecular changes in hippocampal subfields in individuals with schizophrenia (SZ) psychosis associated with hippocampal excitability. In this study, we use RNA-seq and assess global transcriptome changes in the hippocampal subfields, DG, CA3, and CA1 from individuals with SZ psychosis and controls to elucidate subfield-relevant molecular changes. We also examine changes in gene expression due to antipsychotic medication in the hippocampal subfields from our SZ ON- and OFF-antipsychotic medication cohort. We identify unique subfield-specific molecular profiles in schizophrenia postmortem samples compared to controls, implicating astrocytes in DG, immune mechanisms in CA3, and synaptic scaling in CA1. We show a unique pattern of subfield-specific effects by antipsychotic medication on gene expression levels with scant overlap of genes differentially expressed by SZ disease effect versus medication effect. These hippocampal subfield changes could provide the basis for previously observed hippocampal SZ pathology and explain the lack of full efficacy of conventional antipsychotic medication on SZ symptomatology. With further characterization, the identified distinct molecular profiles of the DG, CA3, and CA1 in SZ psychosis may serve to identify potential hippocampal-based therapeutic targets.
Project description:Post-learning sleep plays an important role in hippocampal memory processing, including contextual fear memory (CFM) consolidation. Here, we used targeted recombination in activated populations (TRAP) to label context-encoding engram neurons in the hippocampal dentate gyrus (DG) and assessed reactivation of these neurons during post-learning sleep. We find that post-learning sleep deprivation (SD), which impairs CFM consolidation, selectively disrupts reactivation in inferior blade DG engram neurons. This change was linked to more general suppression of neuronal activity markers in the inferior, but not superior, DG blade by SD. To further characterize how learning and subsequent sleep or SD affect these (and other) hippocampal subregions, we used subregion-specific spatial profiling of transcripts and proteins. We found that transcriptomic responses to sleep loss differed greatly between hippocampal regions CA1, CA3, and DG inferior blade, superior blade, and hilus. Critically, learning-driven transcriptomic changes, measured 6 h following contextual fear learning, were limited to the two DG blades, differed dramatically between the blades, and were absent from all other regions. Similarly, protein abundance in these hippocampal subregions were differentially impacted by sleep vs. SD and by prior learning, with the majority of alterations to protein expression restricted to DG. Together, these data suggest that the DG plays an essential role in the consolidation of hippocampal memories, and that the effects of sleep and sleep loss on the brain are highly subregion-specific, even within the DG itself.
Project description:Post-learning sleep plays an important role in hippocampal memory processing, including contextual fear memory (CFM) consolidation. Here, we used targeted recombination in activated populations (TRAP) to label context-encoding engram neurons in the hippocampal dentate gyrus (DG) and assessed reactivation of these neurons during post-learning sleep. We find that post-learning sleep deprivation (SD), which impairs CFM consolidation, selectively disrupts reactivation in inferior blade DG engram neurons. This change was linked to more general suppression of neuronal activity markers in the inferior, but not superior, DG blade by SD. To further characterize how learning and subsequent sleep or SD affect these (and other) hippocampal subregions, we used subregion-specific spatial profiling of transcripts and proteins. We found that transcriptomic responses to sleep loss differed greatly between hippocampal regions CA1, CA3, and DG inferior blade, superior blade, and hilus. Critically, learning-driven transcriptomic changes, measured 6 h following contextual fear learning, were limited to the two DG blades, differed dramatically between the blades, and were absent from all other regions. Similarly, protein abundance in these hippocampal subregions were differentially impacted by sleep vs. SD and by prior learning, with the majority of alterations to protein expression restricted to DG. Together, these data suggest that the DG plays an essential role in the consolidation of hippocampal memories, and that the effects of sleep and sleep loss on the brain are highly subregion-specific, even within the DG itself.
Project description:This SuperSeries is composed of the following subset Series:; GSE11473: Rapid encoding of information alters the profile of plasticity related mRNA transcripts in the hippocampal CA3 region; GSE11474: Rapid encoding of information alters the profile of plasticity related mRNA transcripts in the hippocampal CA1 region. GSE11475: Rapid encoding of information alters the profile of plasticity related mRNA transcripts in the hippocampal DG region Experiment Overall Design: Refer to individual Series