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Title: Aging and walnut-rich diet supplementation affects the expression of immediate-early genes in critical brain regions

Author
item POULOSE, SHIBU - Jean Mayer Human Nutrition Research Center On Aging At Tufts University
item BIELINSKI, DONNA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University
item CROTT, JIMMY - Jean Mayer Human Nutrition Research Center On Aging At Tufts University
item ROE, ANNIE - University Of Idaho
item Thangthaeng, Nopporn
item Shukitt-Hale, Barbara

Submitted to: Society for Neuroscience Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/25/2015
Publication Date: 10/17/2015
Citation: Poulose, S.M., Bielinski, D.F., Crott, J.W., Roe, A.J., Thangthaeng, N., Shukitt Hale, B. 2015. Aging and walnut-rich diet supplementation affects the expression of immediate-early genes in critical brain regions. Society for Neuroscience Abstracts and Proceedings. Society for Neuroscience Abstracts 2015, Program #767.04.

Interpretive Summary:

Technical Abstract: Emerging evidence indicates a direct link between age-associated changes in epigenetic mechanisms and onset of neurodegenerative diseases, and that these genomic modulations are directly affected by diet. Diets deficient in folate, choline and methionine, or the trace elements zinc and selenium, are reported to induce DNA hypomethylation and are linked to aberrant gene transcription. In a cognitively healthy adult, transcription of immediate-early genes (IEGs) is essential in memory formation and synaptic plasticity. In the current study, we investigated the effect of walnut diets, which are rich in polyunsaturated fatty acids and nutrients such as folate, selenium, magnesium and polyphenolics, on epigenetic mechanisms in critical regions of the brain. Young (3 months, n=30, 10/group) and old (19 months, n=45, 15/group) male Fischer 344 rats were supplemented with control (0%), 6% or 9% walnut diets for 10 weeks. All animals were tested on the radial arm water maze (RAWM) which measures spatial learning and memory. Age-related deficits in cognitive behavior were exhibited in the RAWM. The 9% walnut diet improved performance in the RAWM in both young and old rats. In hippocampus, target gene expression using the comparative CT (''CT) method revealed that differential regulation of IEG signaling exists for the different walnut treatments. Significant aging effects were observed for the expression of BDNF, ARC, EGR1 and AKT1 genes. The most significant difference between 6% and 9% WN was their effect on the RELN and EGR1 genes. BDNF increased among old animals fed with WN diet. In frontal cortex, expressions of target genes were affected by both age as well as diet. Significant increases in the transcript levels of zif268 or EGR, among the 9% WN group could be a factor for the improved memory in that group. Benefits observed with regard to reference memory among animals fed with the 9% walnut diet could possibly be linked to the higher transcript levels of EGR1 in the frontal cortex, which is involved in cognition, long-term memory, and learning.