Cole Guggisberg

headshot of cole guggisburgName: Cole Guggisberg
Hometown: Lafayette, Minnesota
Degree pursuing: Nutrition M.S.
Adviser: Moon-Suhn Ryu

Research focus
Nearly 20-25 mg of iron is needed every day for hemoglobin production and erythropoiesis, with only 1-2 mg coming from the diet. The rest is contributed by iron recycling of senescent red blood cells (sRBCs) by macrophages of the reticuloendothelial system (RES). sRBCs are taken up by macrophages via the process of erythrophagocytosis (EP). Once inside the cell, iron is liberated from heme by heme oxygenase and contributes to the labile iron pool. Due to iron’s reactivity, and potential for creating reactive oxygen species, its regulation is tightly controlled at both the cellular and systemic levels. Iron chaperones, Poly (rC)-binding proteins (PCBPs) play an important role in the shuttling of iron within the cell. PCBP1 binds and delivers iron to the storage protein, ferritin. In prototypical cells, PCBP2 mediates extraction of iron from heme by interacting with heme oxygenase. Additionally, PCBP2 delivers iron to its export system, ferroportin 1. When intracellular iron demand is high, ferritin is degraded by lysosomes via a process known as ferritinophagy. Nuclear receptor coactivator 4 (NCOA4) controls the level of ferritinophagy by acting as a cargo carrier, directing ferritin to autophagosomes for degradation. Elevated levels of intracellular iron causes an increase in lipid peroxidation, leading a form of regulated cell death, ferroptosis. During EP ferritin levels increase, indicating a dynamic change in the cytosolic iron pool. To study the roles and regulation of PCBP1, PCBP2, and NCOA4 in EP, we are employing an in vitro model of EP involving J774 murine macrophages and opsonized RBCs. We aim to determine if the deficiency of these genes impairs macrophage-mediated red cell iron recycling.

How did you become interested in nutrition?
I would say my interest in nutrition developed in high school when I started to appreciate the importance of a healthy diet. Over time I came to realize it was more than just eating healthy that intrigued me, but rather the science behind the nutrients and the functions they perform within the body. I have always enjoyed all types of sciences, but following my time at the University of Minnesota, Morris, I came to realize that I wanted to pursue a career in nutrition, which led me to the Twin Cities campus.

Why did you choose the University of Minnesota?
My first degree is from the Univ. of Minnesota, Morris, which was an all-around exceptional experience, so when I decided to pursue a degree in nutrition there was no other place that I wanted to attend besides the Univ. of Minnesota, Twin Cities.

For my graduate studies I was lucky to meet Dr. Ryu through another faculty member, and after meeting with him and learning about his research goals, I was excited for the opportunity to join his lab and further my education here at the University.

How does your research tie into the research being done in your adviser's lab?
Dr. Ryu’s research focus to date has largely surrounded iron regulation and handling within various cell types, and my research is no different. Macrophages are tasked with an immense iron regulatory role within the body; besides the actual extraction of the iron from red cells, they also act as a temporary iron storage system until there is an increased demand for iron for new red blood cell production. Studying these mechanisms is important for understanding how iron is potentially regulated and handled in various blood disorders.

Future plans
Currently, I am considering pursuing a PhD in Dr. Ryu’s lab. I enjoy many aspects of nutrition and research, and I am looking forward to a potential career in this field.