Sex differences in circadian rhythms underlying diet-induced obesity
Dr. Julie Pendergast
November 22 at 12:20pm in the Fralin Auditorium, 102 Fralin Hall
Hosted by Dr. S. Kojima
Julie Pendergast is an Assistant Professor in the Department of Biology at the University of Kentucky. She received a BS in Cell and Structural Biology and MS in Biology from the University of Illinois, Urbana-Champaign and a PhD in Neuroscience at the University of Miami. She then completed a post-doctoral fellowship at Vanderbilt University. Dr. Pendergast’s major research interest is the circadian regulation of physiology and behavior in mammals. Her lab primarily uses rodent models to study circadian rhythms and how disrupting these rhythms leads to poor health. Specifically, she is interested in the interplay between the circadian and metabolic systems, with a focus on how circadian disruption contributes to obesity and cardiovascular disease, and the sex-specific mechanisms underlying these processes.
Obesity is arguably the greatest threat to the health and financial well-being of people living in Westernized countries. Massive research efforts have focused on understanding the basic mechanisms of obesity with the hope of identifying therapeutics. Disruption of circadian rhythms has been implicated as a risk factor for obesity and as a therapeutic target. In mouse models, we and others have shown that circadian metabolic rhythms are disrupted by high-fat diet feeding in male mice and this disruption causes obesity. Although it is well-established that men and women differ in their susceptibility to obesity-related disorders, no studies have investigated the role of the circadian system in regulating obesity in females. Therefore, we also studied sex differences in circadian mechanisms underlying high fat diet-induced obesity. We found that estradiol regulates daily rhythms of eating behavior, locomotor activity, and molecular tissue rhythms in female mice to confer resistance to diet-induced obesity. Additionally, restoring the daily rhythm of eating behavior in ovariectomized females with time-restricted feeding inhibits diet-induced obesity and insulin resistance. In sum, we find striking estrogen-dependent sex differences in circadian regulation of obesity and identify circadian targets for treating obesity in women.