Improving Islet Transplantation Treatment by Overcoming a Critical Roadblock for Beta-Cell Survival

Dr. Sudipta Ashe
The loss or dysfunction of insulin-producing cells in the pancreas, called beta cells, is the underlying cause of both T1D and T2D. Treating patients with T1D requires frequent insulin injections that cannot control blood glucose levels as efficiently as insulin-secreting beta cells, which are contained in regions of the pancreas called islets. However, islet transplantation as a treatment option is expensive and in short supply. One of the major limitations in clinically successful beta cell transplantation is inadequate vascularization – the failure to grow new blood vessels that provide oxygen and nutrients to the transplanted cells. This lack of oxygen ultimately leads to beta-cell dysfunction and transplant failure. We have achieved considerable success in growing both human embryonic stem cells (hES) and induced pluripotent stem cells (iPS) into functionally mature beta cells (enriched beta cells, eBCs) in the lab. This has the potential to serve as a renewable source of islet beta cells (Nair et al, Nature, 2019). Our project aims to manipulate the genetic makeup of these stem cell-derived beta cells to keep them functionally active for extended periods of time post-transplantation, providing great potential for replacement therapy. Here, we propose to generate “self-healing” beta cells via synthetic gene circuits making them resistant to injury under low-oxygen (hypoxic) conditions.

We plan to generate a novel hypoxia sensor for visualization of hES-derived cells experiencing hypoxia. The sensor cells contain a fluorescent “reporter” that can sense low oxygen in the cells and generate a signal. Next, we will use a similar approach to express an inhibitor of HIF1, a protein that responds to hypoxia. Human embryonic stem cells carrying these synthetic hypoxia sensors and intervention elements will be differentiated into beta cells with our established protocol. Finally, we plan to test the performance of the hypoxia intervention system during transplantation in mice. We expect that our reprogrammed beta cells will show improvements with regard to insulin secretion and will maintain normal blood glucose levels.

The proposed strategy will help overcome a critical roadblock in beta cell survival by detecting and relieving hypoxic stress during early periods of transplantation. Our lab is one of a handful in the world to successfully generate beta cells from human stem cells, and integrating synthetic gene circuits to manipulate optimal functioning will help design treatment strategies for the future.