Changes in cognitive ability and serum microRNAs during aging in mice
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PROVIDER: PRJNA1048312 | ENA |
REPOSITORIES: ENA
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2014-10-01 | E-GEOD-56452 | biostudies-arrayexpress
Project description:Vitamin D is an important calcium-regulating hormone with diverse functions in numerous tissues including the brain. Increasing evidence suggests that vitamin D may play a role in maintaining cognitive function and that vitamin D deficiency may accelerate age-related cognitive decline. Using aging rodents, we attempted to model the range of human serum vitamin D levels, from deficient to sufficient, to test whether vitamin D could preserve or improve cognitive function with aging. For 5-6 months, middle-aged F344 rats were fed diets containing low, medium (typical amount) or high vitamin D3 (100, 1000 or 10,000 IU/kg diet, respectively) and then hippocampal-dependent learning and memory were tested in the Morris water maze. Rats on high vitamin D achieved the highest blood levels (in the sufficient range) and significantly outperformed low and medium groups on maze reversal, a particularly challenging task that detects more subtle changes in memory. In addition to calcium-related processes, hippocampal gene expression microarrays identified pathways pertaining to synaptic transmission, cell communication and G-protein function as being up-regulated with high vitamin D. Basal synaptic transmission also was enhanced corroborating observed effects on gene expression and learning and memory. Our studies demonstrate a causal relationship between vitamin D status and cognitive function and suggest that vitamin D-mediated changes in hippocampal gene expression may improve the likelihood of successful brain aging. Sixty, middle-aged male F344 rats were divided into three groups, each receiving for 5-6 months a different dietary amount of cholecalciferol (vitamin D3; VitD3). Purified AIN-93G (Harlan-Teklad) diet was modified to contain low, medium or high VitD3 (IU/kg diet): High = 10,000, Standard (Control) = 1000; Low = 100. Animal weight and amount of food consumed was recorded 2-3 times/week. Serum levels of 25-hydroxy vitamin D were determined using liquid chromatography/tandem mass spectrometry (ZRT Laboratory). Hippocampal RNA was isolated, quantified and checked for RNA integrity. One low VitD3 sample failed RNA quality control. Remaining RNA samples were applied to Affymetrix Rat Gene 1.0 ST arrays (one array/subject). Pre-statistical filtering removed poorly annotated probe sets, low intensity signals, and outlier values (>2SD of the group mean). Filtered data were analyzed by 1-way ANOVA to identify significant differences and the False Discovery Rate (FDR) procedure was used to estimate the error of multiple testing. FDR was compared at 0.31 and 0.17. Significant genes were assigned to one of four idealized expression patterns using Pearson’s test and separated by the sign of their correlation; relative gene expression values are provided on the log-2 scale. Functional categorization for significant genes was determined using DAVID bioinformatic tools. Please note that 'Marked' and 'Unmarked' (in the sample titles) refers to whether the rat had a mark on its tail. The rats were pair-housed and this is how two rats in one cage were distinguished.
2014-09-23 | E-GEOD-61326 | biostudies-arrayexpress
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2014-09-23 | GSE61326 | GEO
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2020-09-18 | PXD020795 | Pride
Project description:Environmental enrichment has been reported to delay or restore age-related cognitive deficits, however, a mechanism to account for the cause and progression of normal cognitive decline and its preservation by environmental enrichment is lacking. Using genome-wide SAGE-Seq, we provide a global assessment of differentially expressed genes altered with age and environmental enrichment in the hippocampus. Qualitative and quantitative proteomics in naïve young and aged mice was used to further identify phosphorylated proteins differentially expressed with age. We found that increased expression of endogenous protein phosphatase-1 inhibitors in aged mice may be characteristic of long-term environmental enrichment and improved cognitive status. As such, hippocampus-dependent performances in spatial, recognition, and associative memories, which are sensitive to aging, were preserved by environmental enrichment and accompanied by decreased protein phosphatase activity. Age-associated phosphorylated proteins were also found to correspond to the functional categories of age-associated genes identified through transcriptome analysis. Together, this study provides a comprehensive map of the transcriptome and proteome in the aging brain, and elucidates endogenous protein phosphatase-1 inhibition as a potential means through which environmental enrichment may ameliorate age-related cognitive deficits. 4 groups with 3 biological replicates per group: aged in environmental enrichment (EA), aged in standard housing (SA), young in environmental enrichment (EY), and young in standard housing (SY).
2015-06-24 | E-GEOD-43718 | biostudies-arrayexpress
Project description:Recent microarray studies in the hippocampus of rodents or Alzheimerâs disease (AD) subjects have identified a substantial number of cellular pathways/processes correlated with aging and cognitive decline. However, the temporal relationships among these expression changes or with cognitive impairment have not been studied in depth. Here, using Affymetrix microarrays, immunohistochemistry and Morris water maze cognitive testing across 5 age groups of male F344 rats (n=9-15/group, one microarray per animal), we systematically analyzed the temporal sequence and cellular localization of aging changes in expression. These were correlated with performance scores on the hippocampus-dependent Morris Water Maze task. Significant microarray results were sorted in to Early, Intermediate, Midlife, and Late patterns of expression, and functionally categorized (Early- downregulated neural development, lipid synthesis and energy-utilization; upregulated ribosomal synthesis, growth, stress/inflammatory, lysosome and protein/lipid degradation. Intermediate- increased defense/inflammatory activation and decreased transporter activity; Midlife- downregulated energy-dependent signaling and neurite growth, upregulated astroglial activation, Ca2+-binding, cholesterol/lipid trafficking, myelinogenic processes and additional lysosome/inflammation; Late- further recruitment of genes in already-altered pathways). Immunohistochemistry revealed a primarily astrocytic localization of the processes upregulated in midlife, as well as increased density of myelin proteins. Evidence of cognitive impairment first appeared in the 12-month-old group (midlife) and was increased further in the 23-month-old group, exhibiting the highest correlations with some upregulated genes related to cholesterol transport (e.g., Apoe, Abca2), protein management and ion binding. Some upregulated genes for inflammation (Il6st) and myelinogenesis (Pmp22) also correlated with impairment. Together, the data are consistent with a novel sequential cascade model of brain aging in which metabolic alterations early in maturity are followed by inflammation and midlife activation of an astrocyte-centered cholesterol trafficking pathway that stimulates oligodendrocyte remyelination programs. Importantly, this cholesterol trafficking pathway also may compete for astroglial bioenergetic support of neurons, in turn, leading to downregulation of energy-dependent pathways needed to sustain cognitive functions. Experiment Overall Design: Fisher 344 rats aged 3 (n = 9), 6 (n = 9), 9 (n = 9), 12 (n = 9), or 25 (n = 15; but see below) months were behaviorally characterized on the Morris water maze. Briefly, animals were placed in a circular water bath chamber with a partially submerged platform. Three times per day for three days, animals were placed at randomized starting points with the goal of locating the hidden platform. Generally, animals became better at locating the platform, and by the third day of training, were reliably swimming directly to the platform despite randomized starting loci. On the fourth day, the platform was removed and the degree to which the animals focused their searches on the area that previously contained the platform was measured. On the last day of behavior, animals were given a cue trial in which the platform was raised above the water level so that the rats could see it. Measures taken from the behavior study included path length (how long did the animal swim prior to locating the platform/ platform area), latency to platform in seconds, and velocity (centimeters/ second; swim speed). Two aged animals (E2 and E12) were removed from the study for poor health, reducing the 23 month cohort (n = 13). Twelve to twenty four hours after the last behavioral session, animals were killed and their hippocampi removed. The right hippocampus went to immunohistochemistry for quantification and localization of selected protein products. The left hippocampus was dissected, the CA1 region removed and frozen in dry ice prior to microarray processing. mRNA was extracted from each animal's tissue by standard Affymetrix protocols (see Blalock et al., 2003) and hybridized to individual microarrays (RAE 230A; N = 49 arrays in total). Results were processed with the MAS5 algorithm and subjected to âall probe setâ scaling with a target intensity of 500. Probe sets were filtered for presence (> = 5 presence calls study wide) and gene symbol level annotation prior to statistical analysis. 1-ANOVA across age was used to identify aging-related probe sets/genes (p <= 0.05). Aging-related genes were subjected to post hoc template correlation to determine the pattern of age-related change, and further, within the 12 and 23 month old groups, Pearson's correlation with behavioral scores was used to identify genes whose expression levels correlated significantly (p <= 0.05) with behavior. Twelve and 23 month old groups were chosen for this correlation analysis as they showed the greatest variability among similarly aged animals, suggesting that these ages show important cognitive transition phases during aging-related cognitive decline. Functional grouping analysis was performed using the DAVID suite of on-line tools.
2009-01-25 | E-GEOD-9990 | biostudies-arrayexpress
Project description:Functional alterations in medial temporal lobe structures, particularly the hippocampus, are central to age-related deficits in episodic memory. Research in aging laboratory animals has characterized physiological and cellular alterations in the hippocampus that occur in association with the presence and severity of such cognitive impairment. The current study compares alterations across hippocampal subregions by gene expression profiling in a rat model that closely mirrors individual differences in neurocognitive features of aging humans across a spectrum of outcomes, including both impaired memory and preserved function. Using mRNA profiling of the CA1, CA3 and dentate gyrus subregions, we have distinguished between gene groups and pathways related to chronological age and those specifically associated with impaired or preserved cognitive ability in aged rats. We confirmed earlier reported changes in gene groups related to inflammation and oxidative stress in multiple subregions and found these to be more associated with chronological age than cognitive function per se. The CA3 profile was best able to segregate aged impaired, aged unimpaired and young subject groups from each other. Characterization of gene changes that distinguished preserved from impaired function among the aged animals found altered expression of synaptic plasticity and neurodegenerative disease-related genes. Together these gene changes suggest recruitment of adaptive mechanisms that mediate synaptic plasticity to maintain function and structural integrity in aged unimpaired rats that does not occur in aged impaired animals.
2009-11-01 | GSE14724 | GEO