Summary The generation of insulin-producing pancreatic β cells from stem cells in vitro would provide an unprecedented cell source for drug discovery and cell transplantation therapy in diabetes. However, insulin-producing cells previously generated from human pluripotent stem cells (hPSC) lack many functional characteristics of bona fide β cells. Here we report a scalable differentiation protocol that can generate hundreds of millions of glucose-responsive β cells from hPSC in vitro. These stem cell derived β cells (SC-β) express markers found in mature β cells, flux Ca2+ in response to glucose, package insulin into secretory granules and secrete quantities of insulin comparable to adult β cells in response to multiple sequential glucose challenges in vitro. Furthermore, these cells secrete human insulin into the serum of mice shortly after transplantation in a glucose-regulated manner, and transplantation of these cells ameliorates hyperglycemia in diabetic mice.

In vitro differentiation of human stem cells can produce pancreatic β cells; the loss of this insulin-secreting cell type underlies type 1 diabetes. Here, as a step towards understanding this differentiation process, we report the transcriptional profiling of over 100,000 human cells undergoing in vitro β-cell differentiation, and describe the cells that emerged. We resolve populations that correspond to β cells, α-like poly-hormonal cells, non-endocrine cells that resemble pancreatic exocrine cells and a previously unreported population that resembles enterochromaffin cells. We show that endocrine cells maintain their identity in culture in the absence of exogenous growth factors, and that gene-expression changes associated with in vivo β-cell maturation are recapitulated in vitro. We implement a scalable re-aggregation technique to deplete non-endocrine cells and identify CD49a (also known as ITGA1) as a surface marker for the β-cell population, which allows magnetic sorting to a purity of 80%. Finally, we use a high-resolution sequencing time course to characterize gene-expression dynamics during human pancreatic endocrine induction, from which we develop a lineage model of in vitro β-cell differentiation. This study provides a deep perspective on human stem cell differentiation, and will guide future endeavours that focus on the differentiation of pancreatic islet cells, and applications in regenerative medicine.

The transplantation of glucose-responsive, insulin-producing cells offers the potential for restoring glycemic control in diabetic patients1. Pancreas transplantation and the infusion of cadaveric islets are currently implemented clinically2, but are limited by the adverse effects of lifetime immunosuppression and the limited supply of donor tissue3. The latter concern may be addressed by recently described glucose responsive mature β-cells derived from human embryonic stem cells; called SC-β, these cells may represent an unlimited human cell source for pancreas replacement therapy4. Strategies to address the immunosuppression concern include immunoisolation of insulin-producing cells with porous biomaterials that function as an immune barrier5,6. However, clinical implementation has been challenging due to host immune responses to implant materials7. Here, we report the first long term glycemic correction of a diabetic, immune-competent animal model with human SC-β cells. SC-β cells were encapsulated with alginate-derivatives capable of mitigating foreign body responses in vivo, and implanted into the intraperitoneal (IP) space of streptozotocin-treated (STZ) C57BL/6J mice. These implants induced glycemic correction until removal at 174 days without any immunosuppression. Human C-peptide concentrations and in vivo glucose responsiveness demonstrate therapeutically relevant glycemic control. Implants retrieved after 174 days contained viable insulin-producing cells.

We recently reported the scalable in vitro production of functional stem cell-derived β-cells (SC-β cells). Here we extend this approach to generate the first SC-β cells from type 1 diabetic patients (T1D). β-cells are destroyed during T1D disease progression, making it difficult to extensively study them in the past. These T1D SC-β cells express β-cell markers, respond to glucose both in vitro and in vivo, prevent alloxan-induced diabetes in mice and respond to anti-diabetic drugs. Furthermore, we use an in vitro disease model to demonstrate the cells respond to different forms of β-cell stress. Using these assays, we find no major differences in T1D SC-β cells compared with SC-β cells derived from non-diabetic patients. These results show that T1D SC-β cells could potentially be used for the treatment of diabetes, drug screening and the study of β-cell biology.

Significance Human pluripotent stem cells (hPSCs) can be produced from any person and have the potential to differentiate into any cell type in the body. This study focuses on the generation of insulin-expressing cells from hPSCs and compares their gene expression, as assayed by transcriptional gene products, to that of insulin-expressing β cells from human fetal and adult samples. We employ a new method to isolate and profile insulin-expressing cells and conclude that several different hPSC lines generate very similar insulin-expressing cells, cells whose transcripts resemble fetal rather than adult β cells. This study advances the possibility of directing the differentiation of stem cells into functional β cells by comparing and cataloging differences between hPSC-derived insulin-expressing cells and human β cells.

Highlights d Adult human pancreatic beta cells can be induced to proliferate at high rates d Driven by synergy between DYRK1A inhibitors and TGFb superfamily inhibitors d Reflects activation of cyclins and CDKs accompanied by CDK inhibitor suppression d Proliferation occurs in type 2 diabetic beta cells, with enhanced differentiation SUMMARYSmall-molecule inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) induce human beta cells to proliferate, generating a labeling index of 1.5%-3%. Here, we demonstrate that combined pharmacologic inhibition of DYRK1A and transforming growth factor beta superfamily (TGFbSF)/SMAD signaling generates remarkable further synergistic increases in human beta cell proliferation (average labeling index, 5%-8%, and as high as 15%-18%), and increases in both mouse and human beta cell numbers. This synergy reflects activation of cyclins and cdks by DYRK1A inhibition, accompanied by simultaneous reductions in key cell-cycle inhibitors (CDKN1C and CDKN1A). The latter results from interference with the basal Trithorax-and SMAD-mediated transactivation of CDKN1C and CDKN1A.Notably, combined DYRK1A and TGFb inhibition allows preservation of beta cell differentiated function. These beneficial effects extend from normal human beta cells and stem cell-derived human beta cells to those from people with type 2 diabetes, and occur both in vitro and in vivo.

We develop a method to overcome previously documented restrictions on the differentiation propensities of pluripotent stem cells. Culturing pluripotent stem cells in dimethylsulfoxide (DMSO) activates the retinoblastoma protein, increases the proportion of cells in the early G1 phase of the cell cycle, and subsequently improves their competency for directed differentiation into multiple lineages in more than 25 stem cell lines. DMSO treatment also promotes terminal differentiation into functional derivatives.

Cyclin-dependent kinases comprise the conserved machinery that drives progress through the cell cycle, but how they do this in mammalian cells is still unclear. To identify the mechanisms by which cyclin-cdks control the cell cycle, we performed a time-resolved analysis of the in vivo interactors of cyclins E1, A2, and B1 by quantitative mass spectrometry. This global analysis of context-dependent protein interactions reveals the temporal dynamics of cyclin function in which networks of cyclin-cdk interactions vary according to the type of cyclin and cell-cycle stage. Our results explain the temporal specificity of the cell-cycle machinery, thereby providing a biochemical mechanism for the genetic requirement for multiple cyclins in vivo and reveal how the actions of specific cyclins are coordinated to control the cell cycle. Furthermore, we identify key substrates (Wee1 and c15orf42/Sld3) that reveal how cyclin A is able to promote both DNA replication and mitosis.