Harrison in the lab.
Our guest this week on Inspiration Dissemination, Harrison Stierwalt a PhD student in Kinesiology, studies the cellular mechanisms of skeletal muscle physiology. Harrison and other members of the Translational Metabolism Research Laboratory, research the cause of skeletal muscle insulin resistance and how exercise acts against insulin resistance. In particular, Harrison currently studies the activity of a protein called Ras-related C3 botulinum toxin substrate 1, or more commonly known as Rac1. Rac1 plays an important role in the regulation of blood sugar in response to insulin being released from the pancreas following a meal. Insulin is a hormone that triggers the uptake of sugar from the blood stream into skeletal muscle cells where it can be stored or metabolized into energy. In states of insulin resistance, individuals still produce insulin, but eventually insulin resistance leads to chronically increased blood sugar levels. Insulin resistance puts individuals at predisposition for cardiovascular disease, cancer, and type II diabetes. Previous research has demonstrated decreased Rac1 activity in states of insulin resistance but the cause for its decreased activity is unknown.
Harrison working with the oxygraph doing high resolution respirometry (used to measure mitochondrial respiration).
Studying Rac1
The activation of Rac1 causes reorganization of cell components creating “highways” that allow other proteins such as glucose transport 4 or GLUT4 to relocate to the cell membrane and allow sugar from blood to enter skeletal muscle cells for processing. Consequently, Rac1 shows increased activity in response to insulin and exercise promoting the metabolism and storage of sugar in skeletal muscle. Harrison suspects that the dysfunction of Rac1 may play a large role in insulin resistance, and his lab is looking to better understand the dysfunction of skeletal muscle physiology that may contribute to insulin resistance. To study insulin resistance, Harrison is currently comparing Rac1 activity in skeletal muscle cells and skeletal muscle tissue of lean and obese mice. Learn more about Rac1, GO TO ARTICLE.
Harrison has always been drawn to human health, and is particularly intrigued by how adaptable the human body is. He completed his undergraduate degree and Master’s in Exercise Science at Florida State University. After, he worked as a strength and conditioning coach, testing physical performance. While this work was challenging, Harrison decided to pursue a PhD so that he could ask his own research questions about human health and investigate cellular mechanisms therein.
Harrison encouraging a participant during an exercise test.
With a growing interest in metabolism and physiology, Harrison began looking for Kinesiology PhD programs. He discovered the work of his co-advisors, Sean Newsom and Matt Robinson. For Harrison, Oregon State is a good fit that encapsulates his interested: exercise science, molecular cellular biology, and human health. Harrison is starting the second year of his PhD in the College of Public Health and Human Sciences.
If you are interested in participating in human health research, visit the Newsom-Robinson lab webpage.
Tune in this Sunday September 24 at 7 PM to learn more about Harrison and his research with insulin resistance and sugar metabolism. Not a local listener? No sweat! Stream the show live!
You can also download Harrison’s iTunes Podcast Episode!
Mountain biking at Black Rock in Falls City, Oregon.
Harrison at the peak of South Sister, 2017.