Building 3D tissue niches for differentiating human pluripotent stem cells into pancreatic endoderm

The success in directed differentiation of human pluripotent stem cells (HPSC) including embryonic stem (hES) and induced pluripotent stem (iPS) cells into islet-like cells raises new hopes for cell-based diabetes therapy. This, however, has not yet been possible due to the difficulty in generating fully functional beta cells in vitro. In many cases, cells differentiated from HPSCs are immature, or in other words, are unsuitable for cell replacement therapy. Most islet-like cells derived from HPSCs in vitro fail to function normally in vivo after transplantation in diabetic animal models. On the other hand, the in vivo maturation of pancreatic endoderm progenitors presents significant successes. We have developed a new approach to mature HPSC-derived pancreatic endoderm cells into glucose-responsive insulin-secreting cells. We constructed a collagen 3D scaffold and discovered that the maturity of beta-like cells can be considerably elevated when HPSC were differentiated into pancreatic endoderm within an engineered 3D scaffold. This observation was confirmed by both real-time PCR assay and glucose challenging experiments. Furthermore, TEM indicated the existence of insulin-secretion granules in these 3D formed cells, suggesting a high degree of maturation of these cells. This study clearly demonstrated more matured beta-like cells can be generated in vitro. The augment of this technology to other stem cell differentiations will bring cell replacement therapy one step closer to treating many diseases such as diabetes in more controllable clinical settings.