This proposal is a competing renewal of support for our studies of the molecular targets of cell mediated immunity in type 1 diabetes (T1D). In the previous funding period our most significant finding was that the isletspecific zinc transporter ZnT8 is a significant target of both autoantibodies and autoreactive T cells in newly diabetic subjects. A major goal of the current proposal is to extend these observations to determine the therapeutic potential of ZnT8. The holy grail of T1D research is the development of autoantigen-specific therapies that can prevent or arrest disease progression in humans. To date attention has focused mainly on (pro)insulin, HSP60 and GAD65 as potential targets. Although there have been some encouraging results from initial clinical trials, it seems clear that the current protocols need improvement. In humans there is considerable diversity in the natural history of T1D, exemplified by the extreme discordance between individuals in the rate of appearance, titer, and specificity of autoantibodies. This suggests that a one size fits all approach may not be generally successful. The central hypothesis of this proposal is that an antigenspecific therapy capable of being effective in all members of the population cannot rely on a few molecular targets, but rather will require the development of a battery of reagents that target a diverse array of autoantigens. Our proposal focuses on 2 additional autoantigenic targets, IGRP, which was first cloned in one of the applicant s laboratories, and ZnT8, which we were the first to demonstrate to be a major T1D autoantigen during the previous funding period. Prior to conducting clinical trials the efficacy of any novel therapeutic intervention must be established in suitable pre-clinical models. The NOD mouse is generally accepted to be the best small animal model of human T1D currently available, and has been used by many other laboratories to demonstrate proof of concept for new treatments. Thus the primary goal of our proposal is to determine the therapeutic utility of IGRP-derived, and ZnT8-derived reagents for the prevention of spontaneous T1D in NOD mice. It will have 2 specific aims. Firstly, to characterize spontaneously arising autoreactive IGRP and ZnT8-specific CD4+ T cells in NOD mice. The epitope peptides thus identified will provide potential drugs as well as key secondary biomarkers. Secondly, to determine the efficacy of peptide and DNA-based ZnT8 and/or IGRP directed interventions, and the effects of genetic ablation of one or both of these autoantigens. We believe that this study will provide new insight into diabetogenesis in general, and the roles of IGRP and ZnT8 in particular. We anticipate that it will confirm that both autoantigens can be effective therapeutic targets in NOD mice, both early and late during diabetogenesis, and will provide important new insight into the design of drugs and protocols that can ultimately be translated to humans.
Type 1A insulin dependent diabetes mellitus is one of the most frequent chronic diseases of children and young adults, and carries a high risk of devastating complications in later life. It is an autoimmune disease characterized by the selective destruction of the insulin-producing pancreatic ?-cells by autoreactive T-cells. Our proposal will increase knowledge of the molecular targets of the autoreactive cells, and hence will provide new insight into the disease process, and identify novel therapeutic targets and biomarkers.
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