Our overall project goal is to assess the immune response to tissues that are derived from embryonic stem cells. We are using mouse embryonic stem cells (ESC) and the adult mouse as a prototype of a cell-based therapy and a human patient who requires blood stem cells. We are also preparing to use adult diabetic mice as another disease model in the future.
In Years 1 and 2, we optimized our protocols to create embryonic stem cell – derived hematopoietic progenitors (ES-HP). In Year 3, we transplanted ES-HPs into an immune deficient mouse strain, and compared their engraftment, survival and immune cell developmental capacity to that or transplanted adult bone marrow cells. We observed that ES-HP survived up to 3 weeks post-transplantation, and that the ES-HP derived blood cells were located primary in the adult spleen and adult thymus. Furthermore, mice receiving ES-HP displayed large spleens, which is indicative of a local immune response by macrophages. We also were successful in culturing ESC-derived insulin-producing cells (ESC-IPC) cells that have been suggested as a replacement for dysfunctional beta cells and a treatment for diabetes.
In Year 4, our primary goals were to assess ES-HP engraftment capabilities and tolerance induction in the host, and improve ESC-insulin producing cell (ESC-IPC) culture in the laboratory for in vivo experiments. We have determined that increase irradiation dose improves ES-HP engraftment, but that host macrophage specifically phagocytose ES-HP which could affect their long-term survival, and we are now ready to confirm and determine the mechanisms by which macrophages prevent ES-HP engraftment in vivo, in Year 5. We have improved the health of our ESC-IPC cultures but still have the same issues of low insulin release, and we will directly measure the effect of the ESC-IPC in diabetic mice, also by direct transplantation and assessment of ESC-IPC survival, engraftment, and function in Year 5.
This past year, we have published a book chapter on stem cell therapies for diabetes, and published another paper from a distinct project that is related to this work. We also submitted another article that is currently in revision, and we presented our results in poster presentations, short talks and invited research seminars are several scientific conferences and universities in California, New York, and Massachusetts.