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News: Davis wins award in The Obesity Society’s Basic Science Section Poster Competition

October 12, 2016

Stephen  J. Carter, PhD

“Impact of Diet on Time-of-Day-Dependent Rhythms of Short-term Memory,” byJennifer A. Davis, PhD student in UAB’s Genetics, Genomics, and Bioinformatics Graduate Program and T32 graduate trainee in the Nutrition Obesity Research Center (NORC), has been judged by The Obesity Society (TOS) to be one of the best abstracts in the field and placed Ms. Davis among a select group of 10 winners in TOS’sBasic Science Section (BSS) Poster Competition. She will be recognized along with fellow awardees at the annual meeting of the BSS—which supports and promotes “basic scientific efforts to understand the causes and complications of obesity and to identify mechanisms that lead to its prevention or cure”—on November 2, 2016, in New Orleans.

Given the established links between the circadian clock and metabolism—circadian disruption (for example, following shift work) is associated with weight gain, diabetes mellitus, and cardiovascular dysfunction—as well as the profound impact both sleep-wake status and obesity can have on cognitive performance, Ms. Davis and her fellow researchers hypothesized that calorically dense diets alter day-night variations in spatial memory and predicted that these effects may be due to perturbations in the activity of glycogen synthase kinase 3 (GSK3), a molecular regulator of hippocampal-dependent memory and plasticity.

In the study, mice were placed on either a high fat (HFD; 60 percent lard), high sucrose (HSD; 35 percent sucrose), or control diet for 26 weeks. Cognitive function was assessed (via spontaneous alternation performance in a T-maze and two-hour novel object recognition) during the inactive (three hours after lights on) and active (three hours after lights off) periods. Following cognitive assessments, hippocampal tissue was collected every four hours over a 24-hour time course for determination of GSK3α/β phosphorylation via western blot analysis.

Preliminary study results showed a strong trend in the control animals toward improved performance at night, with no significant day/night differences observed in the HFD and HSD groups. Additionally, both the HSD and HFD groups induced a differential shift in the expression pattern of phospho-GSK3α compared with the control animals. The researchers concluded that calorically dense (high fat or high sucrose) diets disrupt time-of-day differences in short-term memory, which is associated with perturbations in GSK3a rhythms.

Co-investigators are researcher assistant Daniel Mount, student assistant Hira Munir, and associate professor Karen L. Gamble, PhD, in the Division of Behavioral Neurobiology; and professor Martin E. Young, DPhil, in the Division of Cardiovascular Disease.