Longitudinal Intravital Imaging of Biosensor-labeled ß-cells and Hepatocytes in Diabetic Mice
Amelia Linnemann   (Indianapolis, IN)
The pathophysiology of metabolic syndrome and diabetes is complex due to the organ crosstalk. In humans and rodents, the pancreatic islet ?-cells and liver hepatocytes play critical roles in regulating blood glucose and lipid homeostasis. In vitro models, including cultured islets and hepatocytes, can be useful tools, however, these primary tissues/cells lack physiological cues from other cells and organs once isolated from the organism. Thus, it is critical to monitor cellular changes in the native environment of a given tissue to fully understand disease progression and consequent organ complications. Here, we describe a novel platform to introduce custom virally-packaged biosensors into diabetic mice to obtain liver and islet specific measurements of cellular function with and without drug interventions. In vivo measurements can be collected from the biosensor-labeled endogenous tissues multiple times when these mice are outfitted with abdominal imaging windows (AIWs). Together, our platform provides a longitudinal method to monitor in vivo tissue physiology as a disease progresses and complications occur, as well as allowing the direct study of tissue function during disease intervention. Our central hypothesis is that both ß-cells and hepatocytes activate autophagy to aid in the mitigation of acute and chronic increases in ROS, and that the timeline of these events are correlated in vivo. When these processes fail, abnormal autophagy and oxidative stress contribute to ß-cell failure and accumulation of lipids in the liver during disease progression. To test this hypothesis and develop a platform for testing of drugs that restore normal antioxidant and autophagy response in vivo, we propose the following Specific Aims: 1. Evaluate redox dynamics longitudinally in vivo in ß-cells and liver. 2. Characterize autophagic flux in vivo in ß-cells and liver. Overall, these experiments will provide proof of principal in vivo evidence for autophagy/antioxidant response coupling and organ crosstalk in the adaptive response to stress and allow us to study direct response to therapies that regulate these processes. My background in ß-cell biology and resources within the Indiana Center for Biological Microscopy makes me uniquely suited to accomplish the aims of this project, which will generate exciting preliminary data towards subsequent R01 funding.
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