My research focuses on how hibernators regulate their metabolism, and how in turn metabolic products and processes can influence or reveal aspects of hibernation physiology. My current projects are listed below and involve both large hibernators (black bears) and small hibernators (arctic ground squirrels):
1) Hibernating bears suppress their metabolism by 75%, but how they do this is unknown. We are working to identify how mitochondrial mechanisms, which consume the majority of oxygen in mammalian cells, are regulated in hibernating bears. We are using multi-organ metabolomics, proteomics, as well as enzyme kinetics to identify major organs in which mitochondrial activity is suppressed.
2) Hibernators undergo prolonged inactivity and long-term fasting, yet small and large hibernators show very little loss of muscle strength, protein balance, or muscle mass compared to human patients who are inactive for equivalent time periods. Arctic ground squirrels display extreme hibernation by fasting up to 8 months with little evidence of muscle loss, making them a perfect model for investigating resiliency to muscle atrophy. We are working to develop methods for measuring physiologically relevant protein, ribosomal (RNA), and mitochondrial synthesis rates in multiple tissues of arctic ground squirrels. This work will lay the ground work for future investigations to elucidate novel molecular mechanisms driving muscle conservation in hibernating animals for translation to human medicine. As protein synthesis is also an energy-intensive process, such work can additionally give unique insight into energy-saving processes in hibernation.
My previous projects have focused on nutrient cycling in hibernating arctic ground squirrels, the influence of fatty acid nutrition on hibernating physiology, and transorgan nutrient flux in critical illness models.