The pathogenesis of type 1 diabetes (T1D) involves islet beta cell loss mediated at a very late stage by cytotoxic T-cells and macrophages. Clinical studies have focused on the administration of immune modulatory drugs at the time of diagnosis, however, in none of these studies has the recovery or durable preservation of beta cell function been achieved. These disappointing outcomes have questioned both our understanding of the pathogenesis of the disease and whether timing of treatment (i.e. earlier in the disease) may yield better outcomes. An unmet need in the field has been the development of simple and reliable biomarkers that can identify those who have a virtually certain or very high likelihood of developing T1D, thereby allowing for earlier treatment interventions. Recent studies from our research Team (Drs. Mirmira, Evans-Molina, Nadler, Metz, and Eizirik) and others suggest the provocative concept that stress pathways triggered within the beta cell very early in T1D evolution may initiate and/or accelerate autoimmune-mediated beta cell destruction. This overdue emphasis on the beta cell offers a unique opportunity to improve current T1D prediction strategies. This application is based on the hypothesis that stressed beta cells of pre-diabetic individuals liberate specific protein and DNA species into plasma, and that measurement of multiple such species can define the beta cell "stress signature" that confers risk for developing T1D. To test this hypothesis, we have assembled an interactive Team of scientists that will collectively engage its proteomics, functional genomics, islet biology, and bioinformatics/statistics expertise to identify protein and nucleic acid-derived biomarkers emanating from stressed beta cells that can stratify better the risk of developing T1D. This project, called "BetaMarker," will take a two-pronged approach: in the first, candidate beta cell-specific protein and nucleic acid biomarkers will be tested in human samples from the DPT-1 and TrialNet PTP cohorts, and in the second, a comprehensive proteomics and functional genomics approach will be undertaken to discover new beta cell-specific biomarkers that will be funneled back into testing in human populations.
Three aims will be achieved: 1.
Aim 1 : Test candidate beta cell-derived protein biomarkers as predictors of T1D risk. 2.
Aim 2 : Validate differentially methylated DNA species as biomarkers of beta cell stress in T1D. 3.
Aim 3 : Identify novel protein and nucleic acid biomarkers of beta cell stress and T1D risk. The impact of the BetaMarker project will be the development of a group of biomarkers that reflect the beta cell "stress signature" and that will serve collectively or as components in a risk score for the development of T1D.
Type 1 diabetes results from dysfunction and death of islet beta cells. The identification of biomarkers that reflect early death of beta cells would allow for the institution of therapies at an early stage of the disease, such that disease can be mitigated or prevented. This application proposes a comprehensive approach to the validation of existing biomarkers of beta cell death and the discovery of new biomarkers that will collectively reflect the signature of stressed beta cells in type 1 diabetes in humans.