Monitoring and increasing resilience of stem cell derived pancreatic islet cell grafts

Project Summary/Abstract Therapeutic options for people living with type 1 diabetes (T1D) are limited to lifelong management of glucose levels with exogenous insulin. Recently, Teplizumab, a CD3 antibody received FDA approval which can delay or halt progression of T1D and may be a cure for some patients. The only other therapeutic option is the transplantation of donor derived pancreatic islets, resulting in a functional cure by negating or easing the life- long need for onerous management with insulin. In addition to being a constant burden on people’s life, exogenous administration of Insulin cannot normalize glucose metabolism due to considerable delayed pharmacokinetics. ß-cell replacement therapy is currently limited by the supply of primary islets as well as a gridlock with the FDA which failed to approve islet transplantation in the US. A recent clinical trial with stem cell derived islets has proven the concept of replacing ß-cells with this unlimited cell source. But major limitations remain, such as the need for immunosuppression which has an unfavorable risk-benefit ratio in most people with Type 1 Diabetes. Allogeneic islet cell grafts face multiple hurdles in the transplant recipient : The first is engraftment in the transplant site which can involve direct exposure to Blood (intraportal infusion) or tissue that has experienced surgical trauma. The subcutaneous and intramuscular transplant sites that we are developing represent an inflammatory environment undergoing tissue repair, which can cause inflammatory stress and death of implanted cells. Second, and most significant hurdle is allogeneic rejection by the host’s immune system. In people with T1D, the potential autoimmune recognition of allogeneic beta cells is another challenge. We have discovered a mechanism that renders beta cells resistant to inflammatory stress induced by cytokines and preventing the loss of beta cells in murine models of autoimmune T1D. This mechanism is mediated by deficiency in the TET2 gene, coding for an enzyme that effects epigenetic modifications. Here we propose to harness that mechanism to develop a sc-Islet product that may overcome the hurdles of non-specific inflammation and targeted immune response in the host. Here we propose to assess the effect of TET2 KO in sc-Islets on cytokine induced inflammatory stress as well as on the allogeneic and antigen-specific, autoimmune cellular immune response. A second product development we are proposing is to leverage our proprietary nanosensor technology to measure the intracellular response to inflammation to enable non- invasive monitoring of the sc-islet graft. There is currently no other method available to detect inflammation in live cells. Our nanosensors detect microRNAs specific to cell states such as inflammation (miR146a) and emit a signal we detect by Raman spectroscopy. These two technologies converge to a product that is more resilient to inflammation and allows detection of a compromised graft prior to more definite readouts such as declining or lost graft function, opening a window for therapeutic intervention such as local or systemic anti- inflammatory or immunosuppressive treatment to prevent graft loss.