Abstract
13C metabolic flux analysis (MFA) is the gold standard approach for quantifying rates of biochemical reactions in living cells. It has been widely applied to debottleneck the metabolism of industrial host organisms, but it is now being increasingly used to investigate metabolic phenotypes of human disease models. My group has applied 13C MFA to quantitatively map the metabolic alterations that occur in liver cells exposed to toxic levels of free fatty acids (FFAs). In humans, abnormal hepatic lipid accumulation caused by FFA overload leads to a condition known as nonalcoholic fatty liver disease (NAFLD), closely associated with obesity and type-2 diabetes and is estimated to affect up to 30% of the U.S. population. Unfortunately, the factors that control disease severity are poorly understood, and therapeutic strategies for preventing or reversing NAFLD are limited.
Based on 13C MFA studies of cultured hepatocytes and hepatic cell lines, we have uncovered a novel lipotoxicity mechanism by which saturated FFAs promote abnormal cell metabolism and oxidative stress in liver cells. This process involves dysregulation of intracellular calcium homeostasis that promotes increased mitochondrial metabolism and accumulation of toxic reactive oxygen species. 13C MFA revealed that metabolic alterations were not driven by increased FFA oxidation, instead were fueled by increased entry of glutamate carbon into the citric acid cycle (CAC). I will discuss these findings as well as my lab’s ongoing work to develop an in vivo 2H/13C MFA approach to simultaneously assess multiple gluconeogenic, CAC, and anaplerotic fluxes in the livers of conscious, unstressed mice; and our lab goal(s).
Speaker Bio
Dr. Jamey D. Young is an Assistant Professor of Chemical and Biomolecular Engineering and Assistant Professor of Molecular Physiology and Biophysics at Vanderbilt University. He received his Ph.D. from Purdue University and was awarded an NSF Graduate Research Fellowship while working in the laboratory of Doraiswami Ramkrishna. Dr. Young continued his training at MIT as an NIH Ruth L. Kirschstein postdoctoral fellow with Gregory Stephanopoulos. The central theme of his research is metabolic engineering: the application of chemical engineering, biochemistry, and molecular biology to analyze and redirect cellular metabolism. In particular, his lab uses13C metabolic flux analysis (MFA) to investigate research questions of relevance to medicine and biotechnology. He was awarded the NSF CAREER Award in 2010 and the DOE Early Career Award in 2012. He has authored over 25 articles and chapters describing application of mathematical modeling and 13C MFA to a variety of research topics, including bacterial physiology, liver metabolism, cancer cell metabolism, photosynthetic metabolism, and cell culture engineering.
