Type 1 Diabetes (T1D) is an autoimmune disorder whereby insulin-producing beta cells are destroyed by the immune system. Diabetogenic CD8+ T cells that recognize islet specific antigens home to the pancreas and initiate an attack on these beta cells. This leads to devastating chronic hyperglycemia and occasional, and life threatening, hypoglycemia. Genetic studies have identified several susceptibility loci that are predictive of T1D, and careful monitoring in the clinic can identify at risk patients who are in a pre-diabetic state. However, despite this knowledge, there exists no reliable method to prevent the initial autoimmune attack on the beta cells or future attacks against transplanted ones. The goal of the work proposed here is to develop a tolerogenic vaccine that is able to interfere with this process and induce regulatory T cells (Tregs) that are protective of islet specific antigens. To do so, this project is aimed at exogenously expressing these antigens in resting dendritic cells (DCs), which are capable of directing a pro-tolerogenic response in the absence of maturation or pro-inflammatory stimuli. To that end, a key challenge is to be able to restrict antigen expression from DCs when they become activated, but maintain robust expression in ones that have not. Our laboratory has recently developed a new microRNA (miRNA) based targeting strategy that is capable of doing just that. By placing target sites for miRNAs that become active upon DC maturation into a transgene, it is possible to completely eliminate expression in activated cells. Therefore, I plan to use viral vectors to deliver islet-specific antigens (Proinsulin and GAD65) to non-activated DCs, and restrict their expression in activated ones by incorporating target sites for miR-155, a miRNA that becomes highly active in mature DCs. I will also use a high-throughput method to identify new miRNAs that can achieve this same goal. These constructs will then be tested to see if they can induce tolerance to Proinsulin or GAD65 and prevent diabetes onset in a NOD mouse model of the disease.

Public Health Relevance

Over 300,000 Americans currently have T1D, and another 30,000 will be diagnosed annually. There exists a pressing need to develop new vaccine based therapies that are capable of halting the immune attack responsible for this disease. This proposal is geared toward the development of one such vaccine, which holds the promise of preventing diabetes in human patients.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Individual Predoctoral NRSA for M.D./Ph.D. Fellowships (ADAMHA) (F30)
Project #
1F30DK095572-01
Application #
8317188
Study Section
Special Emphasis Panel (ZDK1-GRB-R (J1))
Program Officer
Castle, Arthur
Project Start
2012-04-19
Project End
2016-04-18
Budget Start
2012-04-19
Budget End
2013-04-18
Support Year
1
Fiscal Year
2012
Total Cost
$32,990
Indirect Cost
Name
Icahn School of Medicine at Mount Sinai
Department
Genetics
Type
Schools of Medicine
DUNS #
078861598
City
New York
State
NY
Country
United States
Zip Code
10029
Chong, Robert A; Wu, Kenneth; Spratt, Donald E et al. (2014) Pivotal role for the ubiquitin Y59-E51 loop in lysine 48 polyubiquitination. Proc Natl Acad Sci U S A 111:8434-9