The intersection of genetic risk and environmental factors are now known to drive islet autoimmunity, and the breakdown of tolerance caused by this is linked to Regulatory T cells (Tregs), which normally prevent inappropriate immune attack on tissues including beta cells in the pancreas. Thus, Tregs are a prime therapeutic target in T1D, to re-establish islet tolerance. We have taken a two pronged approach to achieving this by: 1) comprehensively mapping the genetic and epigenetic changes in T cells from children at risk of T1D, so that we can, for the first time, connect only the genetic risk active in the T cells to the genes it alters. From this we will identify any immune cell functional changes linked to genetic risk, which can then be tested for therapeutic manipulation in pre- clinical models. The use of the ENDIA longitudinal cohort biobank gives the critical ability to separate causal changes from consequence. We have identified a set of genes and pathways linked to enhancers containing T1D snps, and functionally validated the regulation of these genes by those enhancers using a CRISPr activation approach. From this new targets for intervention can now be screened, and a functional connection between genetic risk and loss of immune function can be made.
The second strategy is to apply a personalised immunotherapy approach to treating islet autoimmunity using CAR technology to reprogram Treg to recognise an islet autoantigen (GAD65) and therefore prevent the activation of GAD specific T cells in vivo. Naïve Tregs were used to generate GAD65 specific CAR Tregs. Following expansion, >80%- of CAR Tregs remain FOXP3 positive. Moreover, their suppressive capacity was not altered by their expression of the CAR., and they proliferate in response to GAD65 protein, suggesting that they are functionally able to recognise GAD65 in vitro. These GAD65-CAR Treg can be further tested in preclinical studies as a method for overcoming GAD65 specific autoimmunity in T1D.