Dave Bridges, PhD
- Associate Professor, Nutritional Sciences
Dr. Bridges is trained as a molecular biologist and biochemist who's research focuses on the regulation of macronutrient metabolism, with a focus on obesity, diabetes and cardiovascular disease. We deploy a variety of cell and mouse models, in combination with human clinical data to better understand how individuals vary in their response to changes in their diets.
- PhD, University of Calgary. 2005
- BS, University of Calgary. 2000
Nutrient sensing, cellular signaling, stress, ketogenic diets, developmental aspects of health and disease, metabolic regulation, energy balance, obesity
Nutrients are sensed by several pathways, but one important signaling mechanism is the protein kinase mTORC1, which integrates the sensing of amino acids, energy and other metabolites and coordinates the cellular responses. These include anabolism, or the storage of nutrients and increases in secretion or conversion of nutrients into energy. We are currently studying the role of mTORC1 in muscle, liver and placental tissues.
Glucocorticoids including cortisol are a class of hormones that are secreted in response to chronic stress. They affect virtually every system of the body, and alter our metabolism to prioritize certain aspects of our physiology (placental/infant growth, glucose flow to the brain, energy supply to the liver). We have found that in both mice and humans, glucocorticoid signaling is altered by obesity. This synergy represents the collision of two public health crises, excessive weight and chronic stress. Our lab is using both mouse models and human clinical data to understand how obesity and stress intersect at a cellular level.
Ketogenic diets and time-restricted feeding are popular but poorly understood at a physiological level. They seem to work very effectively for some people, but are either ineffective or even damaging in others. We are using a precision nutrition approach to understand how individuals vary in their responses to ketogenic diets. This includes both mouse and human studies to understand how genetics, the microbiome, and pre-existing disease affects how we respond to changes in our diets.
Breastmilk is the preferred nutrient source for infants, and is dynamic and variable changing based on the needs and physiology of the mother and child. The most variable component of breastmilk are the lipids, which not only comprise the major energy source for infants, but also the source of essential fatty acids. In collaboration with Dr. Brigid Gregg, we are studying how breastmilk lipids vary within human mothers, for what reasons, and how this affects the health of the mothers. In parallel mouse studies we are evaluating how diet, pharmacology, stress and cellular signaling affect breastmilk including how the mammary gland responds to maternal stimuli to alter breastmilk composition.
Harvey, I., E.J. Stephenson, J.R. Redd, Q.T. Tran, I. Hochberg, N. Qi, D. Bridges. 2018. Glucocorticoid-Induced Metabolic Disturbances are Exacerbated in Obesity. Endocrinology. 159(6):2275-2287. http://dx.doi.org/10.1210/en.2018-00147.
Gunder, L.C. I. Harvey, J. R. Redd, C. S. Davis, A. AL-Tamimi, S. V. Brooks and D. Bridges. 2020. Obesity Augments Glucocorticoid-Dependent Muscle Atrophy in Male C57BL/6J Mice. Biomedicines 8(10): 420 https://doi.org/10.3390/biomedicines8100420.
Carlson, Z., H. Hafner, N. El Habbal, E. Harman, S. Liu, N. Botezatu, M. Alharastani,
H. Reynolds, D. Bridges, B. Gregg. Short Term Changes in Dietary Fat Content and Metformin
Treatment During Lactation Impact Milk Composition and Mammary Gland Morphology. 2022. Journal of Mammary Gland Biology and Neoplasia 27(1):1-18. https://dx.doi.org/10.
Stephenson, E.J., A. Ragauskas, S. Jaligama, J.R. Redd, J. Parvathareddy, M.J. Peloquin, J. Saravia, J.C. Han, S.A. Cormier and D. Bridges. 2016. Exposure to environmentally persistent free radicals during gestation lowers energy expenditure and impairs skeletal muscle mitochondrial function in adult mice. American Journal of Physiology - Endocrinology and Metabolism. 310: E1003-E1015. http://dx.doi.org/10.1152/ajpendo.00521.2015.
Hochberg, I., I. Harvey, Q. Tran, E. J. Stephenson, A.R. Barkan, A.R. Saltiel, W.F.
D. Bridges. 2015. Gene expression changes in subcutaneous adipose tissue due to Cushing's disease. Journal of Molecular Endocrinology 55(2): 81-94. http://dx.doi.org/10.1530/JME-15-0119.
Hatfield, I., I. Harvey. E. R. Yates, J. R. Redd, L. T. Reiter and D. Bridges. 2015. The role of TORC1 in muscle development in Drosophila. Scientific Reports 13(5):9676. http://dx.doi.org/10.1038/srep09676.