Modeling Diabetes in an Integrated Plate System The control of nutrient homeostasis involves the cross talk between multiple organ systems including the gastrointestinal tract, liver, endocrine pancreas, and nervous system, among others. Eating, digestion and nutrient absorption trigger a number of downstream effects on the liver and pancreas that are mediated by nutrients and GI hormones. Type 2 diabetes (T2D) is a metabolic disease that involves all of these organ systems. The most effective cure for T2D is gastric bypass surgery, which is invasive and has complications, but results in improved beta cell function and reversal of insulin resistance in the liver. It is not known why surgery is curative, however the changes in GI hormones that accompany this reversal of T2D are believed to contribute. Current efforts to study the interplay between liver, pancreas and the GI tract have depended on animal models, which often do not recapitulate human physiology. Moreover due to the inter-organ effects of systemic factors like hormones and nutrients, it is challenging to separate direct vs indirect effects on organ systems in vivo. This proposal aims to develop a tractable, high throughput fluidic system containing human pluripotent stem cell (PSC)-derived liver, pancreas and intestine to study inter-organ crosstalk, to identify mechanisms involved in reversal of T2D, and to develop a high throughput-screening platform for basic research and therapeutic screening purposes.
Aim 1 : Develop integrated plate systems that can support organoid function and communication. Manufacture and deliver 36PillarPlate system (UG3) 384PillarPlate (UH3) systems.
Aim 2 : Synthesize tunable hydrogels for robust and reproducible organoid growth and function. Identify biomimetic hydrogels that support the short-term growth of liver, intestinal and pancreatic tissues (UG3) and support organoid function and growth for 4 weeks (UH3).
Aim 3 : Establish liver, intestine, and pancreas organoids in the integrated plate system. Incorporate and test individual organoid systems for function on 36PillarPlate (UG3) 384-well micropillar platform (UH3). Test for organ function and crosstalk for up to 4 weeks.
Aim 4 : Validate the integrated plate system with known therapeutics for T2D (UH3 only).
Modeling Diabetes in an Integrated Plate System Globally, 422 million people have diabetes with a prevalence of 8.5% in 2014 (World Health Organization). Diabetes was the direct cause of 1.6M deaths, and indirectly associated with another 2.2M. The majority of cases of diabetes are associated with obesity and regimented caloric restriction and regular exercise can improve the glycemic control of many patients. However, all studies agree that most patients do not adhere to these strict life style changes and that metabolic changes associated with obesity and T2D become physiologically entrenched. The most effective strategy to reverse T2D is bariatric surgery, which lowers blood sugar in 90% of patients and results in remission in 75% of the time. The glycemic improvement occurs within weeks of surgery, well before any loss of weight. This indicates that the surgical changes in the GI tract play a significant role in glucose normalization. The exact mechanism by which this occurs is unknown, and this application focuses on this critically significant clinical question. Disease modeling and drug discovery in animal models is often inaccurate due to significant differences between animals and humans. Such preclinical evaluations are considered to be among the most problematic steps in drug discovery. Many pharmacologic approaches to treat diabetes target the gastrointestinal (GI) tract, beta cells, or liver, yet historically there have been no human models of these organs on which to discover and test new drugs. Our scientists have developed human intestinal, liver and pancreatic tissues from pluripotent stem cells (PSCs) that have a high degree of functionality. However, current culture systems are low throughput and do not allow for culturing of multiple tissue types simultaneously. The premise of this project is that existing in vitro and in vivo systems are inadequate to understand metabolic control of nutrient homeostasis in humans. Our goal is to generate a human PSC- derived intestinal, liver and endocrine pancreatic tissues in an integrated plate system consisting of a 384- pillar plate with sidewalls and slits (384PillarPlate) and a complementary 384-perfusion plate with microchannels (384PerfusionPlate). We propose to use this system as an in vitro model of human T2D. Development of such a platform would have a profound impact on our ability to study human organ function, organ-organ communication, and drug discovery efforts focused on T2D.
