ABSTRACT: FFK506-Binding Protein 12.6/1b, a negative regulator of [Ca2+], rescues memory and restores genomic regulation in the hippocampus of aging rats
Project description:Hippocampal overexpression of FK506-binding protein 12.6/1b (FKBP1b), a negative regulator of ryanodine receptor Ca2+ release, reverses aging-induced memory impairment and neuronal Ca2+ dysregulation. Here, we test the hypothesis that FKBP1b also can protect downstream transcriptional networks from aging-induced dysregulation. We gave hippocampal microinjections of FKBP1b-expressing viral vector to male rats at either 13-months-of-age (long-term) or 19-months-of-age (short-term) and tested memory performance in the Morris water maze at 21-months-of-age. Aged rats treated short- or long-term with FKBP1b substantially outperformed age-matched vector controls and performed similarly to each other and young controls. Transcriptional profiling in the same animals identified 2342 genes whose hippocampal expression was up-/down-regulated in aged controls vs. young controls (the aging effect). Of these aging-dependent genes, 876 (37%) also showed altered expression in aged FKBP1b-treated rats compared to aged controls, with FKBP1b restoring expression of essentially all such genes (872/876, 99.5%) in the direction opposite the aging effect and closer to levels in young controls. This inverse relationship between the aging and FKBP1b effects suggests that the aging effects arise from FKBP1b deficiency. Functional category analysis revealed that genes downregulated with aging and restored by FKBP1b associated predominantly with diverse brain structure categories, including cytoskeleton, membrane channels and extracellular region. Conversely, genes upregulated with aging but not restored by FKBP1b associated primarily with glial-neuroinflammatory, ribosomal and lysosomal categories. Immunohistochemistry confirmed aging-induced rarefaction, and FKBP1b-mediated restoration, of neuronal microtubular structure. Thus, a previously-unrecognized genomic network modulating diverse brain structural processes is dysregulated by aging and restored by FKBP1b overexpression.
Project description:The current study employed next generation RNA sequencing using two different platforms (Illumina and Ion Proton) to examine gene expression differences related to brain aging, cognitive decline, and hippocampus subregions (CA1, CA3, DG). Young and aged rats were trained on a spatial episodic memory task. The results describe regional differences in gene expression and point to regional differences in vulnerability to aging. Aging was associated with increased expression of immune response related genes, particularly in the dentate gyrus. For the memory task, impaired performance of aged animals was linked to the regulation of Ca2+ and synaptic function in region CA1. Finally, we provided a transcriptomic characterization of the three subregions regardless of age or cognitive status, highlighting and confirming a correspondence between cytoarchitectural boundaries and molecular profiling.
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:Among all voltage-gated calcium channels, the T-type Ca2+ channels encoded by the Cav3 genes are highly expressed in the hippocampus, which is associated with contextual, temporal and spatial learning and memory. However, the specific involvement of the Cav3.2 T-type Ca2+ channel in these hippocampus-dependent types of learning and memory remains unclear. To investigate the functional role of the 1H channel in learning and memory, we subjected Cav3.2 homozygous, heterozygous knockout and their wild-type littermates to hippocampus-dependent behavioral tasks, including trace fear conditioning (TFC), the Morris water-maze and passive avoidance. The Cav3.2-/- mice performed normally in the Morris water-maze and auditory trace fear conditioning tasks but were impaired in the context-cued trace fear conditioning, step-down and step-through passive avoidance tasks. Furthermore, long-term potentiation (LTP) could be induced for 180 minutes in hippocampal slices of WTs and Cav3.2+/- mice, whereas LTP persisted for only 120 minutes in Cav3.2-/- mice. To determine whether the hippocampal formation is responsible for the impaired behavioral phenotypes , we next performed experiments locally knock down function of the Cav3.2 T-type Ca2+ channel in the hippocampus. Wild-type mice infused with mibefradil exhibited similar behaviors as homozygous knockouts. Finally, microarray analyses indicated that Cav3.2-/- and WT mice presented distinct hippocampal transcriptome profiles. Taken together, our results demonstrate that retrieval of context-associated memory is dependent on the Cav3.2 T-type Ca2+ channel. After WT and Cav3.2 KO mice retrieval of context-associated memory, three right hippocampi of each group were dissected, pooled together and homogenized. The products of experimental and naive groups were used to acquire expression profiles of a total of 29,922 unique genes. Two replicates per group.
Project description:Among all voltage-gated calcium channels, the T-type Ca2+ channels encoded by the Cav3 genes are highly expressed in the hippocampus, which is associated with contextual, temporal and spatial learning and memory. However, the specific involvement of the Cav3.2 T-type Ca2+ channel in these hippocampus-dependent types of learning and memory remains unclear. To investigate the functional role of the 1H channel in learning and memory, we subjected Cav3.2 homozygous, heterozygous knockout and their wild-type littermates to hippocampus-dependent behavioral tasks, including trace fear conditioning (TFC), the Morris water-maze and passive avoidance. The Cav3.2-/- mice performed normally in the Morris water-maze and auditory trace fear conditioning tasks but were impaired in the context-cued trace fear conditioning, step-down and step-through passive avoidance tasks. Furthermore, long-term potentiation (LTP) could be induced for 180 minutes in hippocampal slices of WTs and Cav3.2+/- mice, whereas LTP persisted for only 120 minutes in Cav3.2-/- mice. To determine whether the hippocampal formation is responsible for the impaired behavioral phenotypes , we next performed experiments locally knock down function of the Cav3.2 T-type Ca2+ channel in the hippocampus. Wild-type mice infused with mibefradil exhibited similar behaviors as homozygous knockouts. Finally, microarray analyses indicated that Cav3.2-/- and WT mice presented distinct hippocampal transcriptome profiles. Taken together, our results demonstrate that retrieval of context-associated memory is dependent on the Cav3.2 T-type Ca2+ channel. After WT and Cav3.2 KO mice retrieval of context-associated memory, three left hippocampi of each group were dissected, pooled together and homogenized. The products of experimental and naive groups were used to acquire expression profiles of a total of 29,922 unique genes. Two replicates per group.
Project description:This study focused on transcription in the medial PFC (mPFC) as a function of age and cognition. Young and aged F344 rats were characterized on tasks, attentional set shift and spatial memory, which depend on the mPFC and hippocampus, respectively. Differences in transcription associated with age and cognitive function were examined using RNA sequencing to construct transcriptomic profiles for the mPFC, white matter, and region CA1 of the hippocampus. The results indicate regional differences in vulnerability to aging associated with increased expression of immune and defense response genes and a decline in synaptic and neural activity genes. Importantly, we provide evidence for region specific transcription related to behavior. In particular, expression of transcriptional regulators and neural activity-related immediate-early genes (IEGs) are increased in the mPFC of aged animals that exhibit delayed set shift behavior; relative to age-matched animals that exhibit set shift behavior similar to younger animals. The study contains 11 young and 20 aged rats for the mPFC and CA1 samples, which were used to investigate expression patterns associated with aging and behavior. White matter samples were used to investigate an age-related effect with 8 young and 9 aged rats.
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:This project examined changes in degradation-specific K48 polyubiquitination in the hippocampus across the lifespan and during memory formation in old age in rats.
Project description:This project examined changes in degradation-specific K48 polyubiquitination in the hippocampus across the lifespan and during memory formation in old age in rats.
Project description:This project examined changes in degradation-specific K48 polyubiquitination in the hippocampus across the lifespan and during memory formation in old age in rats.