Diabetes

Genetic engineering in human pancreatic cells

In Type I, juvenile diabetes, the insulin producing beta-cells in pancreatic islets are destroyed by the immune system and patients require exogenous insulin. In Type II diabetes beta-cells are also lost or dysfunctional and therefore, 25% of patients with Type II diabetes also take insulin. Unfortunately, current insulin therapy is not sufficient to prevent serious medical consequences of this disease. Islet transplantation into the liver has been evaluated as a diabetes therapy in adults. However, it is considered too risky for children because transplant patients must take potent drugs to suppress the immune system for the rest of their lives.

Human pancreas development

The goal of our lab is to develop a human islet transplantation therapy for children which does not require immunosuppression and is minimally invasive. Previously we determined that a durable encapsulation device protected mouse islets from immune rejection in a mouse model of Type I diabetes. The encapsulated cells were controlled diabetes in the animals. In a preclinical trial we demonstrated that the device is also immunoprotective in primates. Recently we have collaborated with a local biotech company ViaCyte in a CIRM funded study to encapsulate human embryonic stem cell derived pancreas cells. Together we demonstrated that the cells differentiate into fully functional islets inside the device and cure diabetes in mice. Remarkably, the cells functioned well even when the device was transplanted just under the skin, making the procedure minimally invasive.

Islet clusters in the developing pancreas

We also study the signaling pathways involved in:

• beta-cell differentiation
• beta-cell function
• beta-cell replication and regeneration

Pancreatic Cancer

Id3 (green) in human pancreatic cancer

We are interested in identifying the master regulators of growth control in pancreatic ductal adenocarcinoma (PDA). We found that the transcriptional repressor Id3 is profoundly upregulated in human PDA. To investigate whether Id3 might play an early role in aberrant pancreatic duct cell growth, we expressed the gene in primary human duct cells which are not normally growing. Indeed, Id3 expression was sufficient to trigger cell cycle entry. Further, the lab demonstrated that Id3 is required for pancreatic cancer cell growth. We are now studying Id3 interacting genes in order to identify optimal targets for drug discovery efforts for PDA.