The overall goal of this proposal is to identify means for improving ? cell regeneration in the adult pancreas. With previous help of NIH/NIDDK funding we developed a transgenic model of inducible total or partial ? cell ablation (termed RIP-DTR). We have reported that in these mice there is spontaneous reconstitution of new ? cells from heterologous (i.e. non-? cells after near-total ? cell loss. The RIP-DTR model has revealed an unsuspected degree of cellular plasticity in the pancreas of juvenile and adult mice, including aged individuals, regarding the spontaneous inherent capacity of islet ? cells and ? cells to switch to insulin production upon ? cell loss. During the next 5 years we want to address the following fundamental questions: 1. What is (are) the signal(s) driving ? cell reprogramming upon near-total ? cell ablation? 2. Can the ? cell to-? cell conversion be fostered? Why only a small fraction of ? cells engages into conversion? What is the nature of the epigenetic modifications in reprogrammed ? cells? 3. Can human ? cells reprogram to insulin production? 4. What is the influence of ageing on islet cell plasticity? 5. Can other islet cells, i.e. besides ? cells, reprogram to insulin production? Specifically, the proposed aims are as follows:
Aim1 : Pathways and factors promoting/facilitating ? cell reprogramming in mice and human Aim2: Pathways and factors promoting/facilitating ? cell reprogramming in mice and human Aim3: In vivo (whole body) tissue screening to identify new cell sources with high plasticity potential to convert toward the ? cell phenotype Description of Aims 1 and 2: We previously reported that ? cells do reprogram to insulin production after ? cell loss in adult mice. We have now discovered (MS under revision) that ? cells efficiently reprogram to insulin production after total ? cell loss in prepubescent mice, leading to 100% diabetes recovery. We plan to study: 1- What are the instructive signals and which signaling pathways coordinate ? cell and - ? cell conversion? 2- Why ? cell conversion is temporally restricted to young mice, while ? cell conversion only occurs after puberty? 3- Are ? cell and ? cell conversion mechanisms mutually exclusive? 4- Can in vivo ? cell and ? cell conversions be facilitated by means of compounds mimicking the effect of instructive signals? 5- Are human islets endowed with cell plasticity capabilities? How diabetic conditions influence i) the capacity of human/mouse ? cell and ? cells to reprogram, and ii) the maintenance of the ? cell phenotype? Description of Aim 3: Given the potential clinical impact of cell reprograming considered broadly, we also plan to explore other target cell types for their capacity for trans-fating into a ? cell-like phenotype. We plan to study: 1- What tissues are susceptible of undergoing cell reprogramming? What are the optimal conditions for cell reprogramming in situ? Would ectopic extra-pancreatic beta-like cells function properly? 2- Can transplantable functional insulin-producing cells be obtained ex vivo from patient-derived primary cells?
A cure for insulin-dependent diabetes requires the reconstitution of sufficient insulin-producing cell numbers, either through regeneration within the pancreas, or by transplanting surrogate cells grown in the laboratory. The overall goal of this proposal is to identify solutions for improving insulin-producing cell regeneration in adults. Recent work from our group, performed thanks to the support of the NIH/NIDDK (Beta Cell Biology Consortium), the Juvenile Diabetes Research Foundation (JDRF) and the Swiss National Science Foundation (NRP 63 Stem Cells and Regenerative Medicine), indicates that new insulin-producing cells may form in the adult pancreas from pancreatic cells that initially do not express insulin. We have already validated in human cells some key findings obtained in mouse models generated in our laboratory. OMB No. 0925-0001/0002 (Rev. 08/12 Approved Through 8/31/2015)Page 1 Continuation Format Page