Title: A Novel Mechanism for Protection Against Obesity Mediated by Kir2.1

Abstract: Obesity is a worldwide epidemic which has a variety of negative health consequences including diabetes, cardiovascular disease, and liver steatosis. My overarching goal for this project is to develop a novel mechanistic understanding of obesity as mediated by palmitic acid leading to endothelial dysfunction. We have discovered that a mutation that leads a ubiquitous K+ channel, Kir2.1 to become cholesterol insensitive (substitution of leucine at position 222 with isoleucine) is protective against obesity and liver steatosis in mice on high fat diet. We have also shown that Kir2.1 channels are suppressed by palmitic acid which is a primary driver of obesity. In this project, I will evaluate the hypothesis that the loss of Kir2.1 function plays a major role in the development of obesity via palmitic acid suppression of the channel, whereas the L222I mutation that preserves Kir2.1 function is protective. Additionally, I have performed flow-induced vasodilation experiments and electrophysiology experiments on endothelial cells which indicated that Kir2.1-L222I is protective against obesity induced suppression and that palmitic acid suppresses Kir2.1 channel current. In aim 1, I will determine whether the differences in body composition are due to increased activity and further elucidate a link between Kir2.1-mediated endothelial dysfunction and obesity. I will perform this study using three different animal models, including two endothelial specific, and three different metabolic parameters NMR, running wheels, and movement telemetry. The goal of aims 2 is to elucidate the mechanism by which obesity-associated palmitic acid suppresses Kir2.1 and the protection afforded by the Kir2.1-L222I mutation. To accomplish these aims I will perform electrophysiology on primary and cultured endothelial cells, perform western blot, and complete structural and docking analysis. The experiments proposed in this project will allow me to further develop skills in metabolic research, electrophysiology, and animal research. I will also continue developing conceptual knowledge in vascular ion channel biology and the role of ion channels in metabolism. I will also work with Dr. Levitan on scientific communication and professional development. I will take full advantage of the opportunities for training available to me at the University of Illinois-Chicago and throughout the region.