Human Performance Clinical Research Laboratory Extracellular Regulation of Metabolism Laboratory

We study how EVs change in response to exercise, food or diseases like obesity in the blood of human subjects.  Thus far, these projects have been retrospective, meaning we obtain blood samples studies have been performed by other research groups.  This is advantageous because it allows us to analyze the EVs in relation to demographic and physiological data.  In the future, we plan to conduct prospective studies in which we recruit and study human subjects in our laboratory using dietary, physical or pharmacological interventions.

An important piece of our research program is the use of mice and cultured cells.  We create genetically engineered mice to study where EVs are coming from and how their secretion is regulated.  To do this, we created a mouse where different cell types (i.e. skeletal muscle myocytes) are “color-coded” so we can track the origin of EVs from different cells in vivo.  We have also developed an ex vivo method where we place cells or tissues in a dish and treat them with various chemicals to mimic exercise or overnutrition.  We can also use chemicals targeting specific signaling pathways to try to identify the cellular mechanisms regulating EVs secretion.

We use both conventional molecular biology (i.e. western blotting and PCR) and highly specialized approaches to study EVs.  For example, we use nanoparticle tracking analysis (NTA) to measure EVs size and abundance.  This approach involves firing lasers at EVs and then using a very sensitive camera to measure how fast they move.  Their rate of movement tells us their size, and the number of particles tells us their abundance.  We also use flow cytometry, which as the name indicates, is designed for cells.  Extracellular vesicles are much smaller (~100x) than cells, but we have developed a method that allows us to study EVs using this instrument.  We use flow cytometry to define the origin of EVs (using the “color-coded” mouse described above) and analyze the composition of EVs using antibodies that target specific surface markers.