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).
Project description:Background: Age-related cognitive deficits negatively affect quality of life and can presage serious neurodegenerative disorders. Despite sleep disruption’s well-recognized negative influence on cognition, and its prevalence with age, surprisingly few studies have tested sleep’s relationship to cognitive aging. Methodology: We measured sleep stages in young adult and aged F344 rats during inactive (enhanced sleep) and active (enhanced wake) periods. Animals were behaviorally characterized on the Morris water maze and gene expression profiles of their parietal cortices were taken. Principal Findings: Water maze performance was impaired, and inactive period deep sleep was decreased with age. However, increased deep sleep during the active period was most strongly correlated to maze performance. Transcriptional profiles were strongly associated with behavior and age, and were validated against prior studies. Bioinformatic analysis revealed increased translation and decreased myelin/ neuronal pathways. Conclusions: The F344 rat appears to serve as a reasonable model for some common sleep architecture and cognitive changes seen with age in humans, including the cognitively disrupting influence of active period deep sleep. Microarray analysis suggests that the processes engaged by this sleep are consistent with its function. Thus, active period deep sleep appears temporally misaligned but mechanistically intact, leading to the following: first, aged brain tissue appears capable of generating the slow waves necessary for deep sleep, albeit at a weaker intensity than in young. Second, this activity, presented during the active period, seems disruptive rather than beneficial to cognition. Third, this active period deep sleep may be a cognitively pathologic attempt to recover age-related loss of inactive period deep sleep. Finally, therapeutic strategies aimed at reducing active period deep sleep (e.g., by promoting active period wakefulness and/or inactive period deep sleep) may be highly relevant to cognitive function in the aging community. KEYWORDS: frontal cortex, rat, young or aged We implanted young and aged Fischer 344 rats (n = 6/ group) with wireless EEG, EMG and movement monitoring devices to measure sleep architecture. Animals were trained in the Morris water maze to assess cognitive function, and frontal cortices were removed for microarray analysis.sleep disruption and cognitive decline.
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:We show that platelet factors transfer rejuvenating effects of young plasma to the aging brain. Proteomic analysis of plasma from young and aged mice identified age-related changes in platelets. Systemic exposure of aged animals to the platelet fraction of young plasma decreased hippocampal neuroinflammation at a transcriptional and cellular level and ameliorated cognitive impairments. We identified the platelet-derived chemokine CXCL4/Platelet Factor-4 (PF4) as a pro-youthful circulating factor. Systemic PF4 administration decreased age-related neuroinflammation, restored the aging peripheral immune system to a more youthful state, and improved hippocampal-dependent learning and memory in aged mice.
Project description:Repeated excessive alcohol consumption increases the risk of developing cognitive decline and dementia. Hazardous drinking among older adults further increases such vulnerabilities. In order to understand the molecular mechanisms underlying alcohol-induced cognitive deficits in older adults, we performed a chronic intermittent ethanol exposure paradigm (ethanol or water gavage every other day 10 times) in 8-week-old young adult and 70-week-old aged rats. While spatial memory retrieval ascertained by probe trials in the Morris water maze was not significantly different between ethanol-treated and water-treated rats in both age groups after the fifth and tenth gavages, behavioral flexibility was impaired in ethanol-treated rats than water-treated rats in the aged group but not in the young adult group. Further proteomic and phosphoproteomic analyses on their hippocampal tissues by tandem mass tag mass spectrometry revealed ethanol-treatment-associated proteomic and phosphoproteomic differences distinct to the aged rats, including the upregulations of Prkcd protein level, several of its phosphosites, and its kinase activity and the same aspects in Camk2a but downregulated, and were enriched in pathways involved in neurotransmission regulation, synaptic plasticity, neuronal apoptosis, and insulin receptor signaling. In conclusion, our behavioral and proteomic results added several candidate proteins and pathways potentially associated with alcohol-induced cognitive decline in aged adults.
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.
Project description:Mechanisms contributing to age-related cognitive decline are poorly defined. Thus, we used canine microarrays to compare gene expression profiles of brain tissue from geriatric and young adult dogs. Cerebral cortex samples were collected from 6 geriatric (12 yr-old) and 6 young adult (1 yr-old) female beagles after being fed one of two diets (animal protein-based versus plant-protein based) for 12 months. RNA samples were hybridized to Affymetrix GeneChip Canine Genome Arrays. Statistical analyses indicated that the age had the greatest impact on gene expression, with 963 transcripts differentially expressed in geriatric dogs. Although not as robust as age, diet affected mRNA abundance of 140 transcripts. As demonstrated in aged rodents and humans, geriatric dogs had increased expression of genes associated with inflammation, stress response, and calcium homeostasis and decreased expression of genes associated with neuropeptide signaling and synaptic transmission. In addition to its existing strengths, availability of gene sequence information and commercial microarrays make the canine a powerful model for studying the effects of aging on cognitive function. Keywords: age; diet
Project description:We test the idea that peripheral cellular senescence is a major driver of age-related cognitive impairment, such that treatment with the brain impermeable senolytic, ABT-263, can preserve cognition and markers of brain aging thought to underlie cognitive decline. Male F344 rats were treated from 12-18 months of age with quercetin + dasatinib or ABT-263 or vehicle and were compared to young (6 month). Senolytic treatments had similar effects in decreasing peripheral markers of senescence and the senescence-associated secretory phenotype (SASP), including plasma levels of several cytokines, rescued memory and hippocampal synaptic transmission, and decreased expression of immune response genes in the dentate gyrus (DG). Across senolytic treatment groups, differential DG gene expression was observed for cellular senescence and pathways linked to senescence, including negative regulation of cell death, ribosomes, and microglial activation consistent with differential access of dasatinib and ABT-263 to the brain. Finally, both senolytic treatments preserved the blood-brain barrier suggesting that leakage of clinically significant amounts of ABT-263 into the brain is unlikely. The results indicate that preserved cognition was due to removal of peripheral senescent cells, decreasing systemic inflammation that normally drives neuroinflammation, BBB breakdown, and impaired synaptic function.