The goal of this project is to provide a source of surrogate b-cells that will be suitable for treatment of insulin-dependent diabetes mellitus (IDDM). The applicant has recently targeted preproinsulin expression to the intermediate lobe (IL) of the pituitary in transgenic nonobese diabetic (NOD) mice, a model of human IDDM. The IL pituitary cells isolated from these mice secrete mature insulin via a regulated secretory pathway, similar to islet b-cells. However, in contrast to insulin producing islet b-cells, the insulin producing IL pituitary cells are not attacked by cells of the immune system when the cells are transplanted under the kidney capsule in NOD mice. Further, transplantation of the transgenic IL tissues into diabetic NOD mice resulted in restoration of near-normoglycemia and reversal of other diabetic symptoms. The absence of autoimmunity in intermediate lobe pituitary cells engineered to secrete bone fide insulin has suggested that these cells may have potential for treatment of IDDM. The major objective of the project is to introduce into the insulin-secreting IL tissues the ability to secrete insulin in response to glucose and other physiological secretagogues (e.g., meals). The requirements for glucose sensing will initially be tested utilizing a recombinant adenovirus gene delivery system. Subsequently, the optimal components will be stably expressed in the insulin secreting IL tissues of NOD mice using transgenic techniques. The applicant will then assess whether these bioengineered tissues, when transplanted into NOD mice, can lead to the long term normalization of glucose homeostasis and whether they can still avoid the autoimmune destructive process targeted against b-cells in IDDM. These strategies may create a novel source of 'artificial b cells' for diabetes treatment and provide important insights into the biochemical requirements for glucose sensing.
| Faradji, R N; Havari, E; Chen, Q et al. (2001) Glucose-induced toxicity in insulin-producing pituitary cells that coexpress GLUT2 and glucokinase. Implications for metabolic engineering. J Biol Chem 276:36695-702 |
| Koya, D; Dennis, J W; Warren, C E et al. (1999) Overexpression of core 2 N-acetylglycosaminyltransferase enhances cytokine actions and induces hypertrophic myocardium in transgenic mice. FASEB J 13:2329-37 |
