|Ph.D Student||Fodor Adriana|
|Subject||Construction of Glucose-Sensitive Insulin Secreting Cells|
from Liver and Adipose Cells: A Model of Ex Vivo
Gene Therapy for Type 1 Diabetes
|Department||Department of Medicine||Supervisor||Professor Emeritus Eddy Karnieli|
|Full Thesis text|
The major goal of current diabetes research is to generate an abundant source of glucose-responsive insulin-secreting cells, ready for transplantation in order to cure type 1 diabetes.
Thus, the purpose of this study was to construct a model of ex vivo gene therapy using an autologus source of glucose responsive insulin secreting cells (beta-cell like). Using a human lentiviral vector carrying human PDX-1 gene, primary mature hepatocytes and human preadipocytes were in vitro transduced with PDX-1.
Using this vector, we ex vivo engineered primary hepatocytes to function in vitro and in vivo as beta cells. The engineered cells exhibited distinct regulatory beta cell-like functions: they secreted insulin in response to glucose and secretagogues in a dose dependent manner; morphologically rearrange like beta cells in vitro as well as in rat liver in vivo; were able to normalize in vivo plasma glucose levels of diabetic mice when implanted under the animal kidney capsule; and reversed the weight loss associated with the disease in SCID diabetic mice. These functions are essential to the control of glycemia in humans as well as other mammals.
When we examined the potential of human preadipocytes to transdifferentiate to beta cells, we found that expression of PDX-1 into in vitro differentiated preadipocytes induced the expression of an important set of pancreatic genes, including insulin. While the in vitro engineered preadipocytes were transplanted into diabetic SCID mice, fasting blood glucose levels returned to control levels.
Thus, ex vivo gene therapy by lentiviral mediated human PDX-1, using isolated liver cells or human adipose cells, can normalize glucose homeostasis in diabetic mice, and presents a potential mode for future cure of type 1 diabetes.