Assistant Professor Karolinska Institutet Stockholm, Sweden
Abstract: Type 1 diabetes (T1D) is an autoimmune disease where immune cells destroy the insulin producing pancreatic beta cells. Pancreas or islet transplantation is a promising treatment and provide a better glucose homeostasis in T1D patients. However, limited availability of donors, poor yield of islets and immune rejection are the major obstacles with primary islet or pancreas transplantation. Yet stem cell derived islets (SC-islets) provide an alternative to overcome challenges associated with primary islet transplantation. Although, several protocols have been developed by different labs, the composition and purity of these SC-islets remains a challenge. SC-islets, from most of the protocols, contains approximately 20% to 50% unwanted or off-target cells (ductal, exocrine and enterochromaffin cells) apart from the intended alpha and beta cells. Preclinical studies have shown that such unwanted cells are associated with unwanted cell growth following transplantation. Therefore, eliminating these unwanted cells is important for the safety of clinical testing. Furthermore, published SC-islets have only show in vitro functionality with approximately 2-5-fold increased insulin secretion following high glucose challenge, which is significantly lower than high quality pancreatic islets.
In this study we have used multiomic CITE-Seq and flow cytometry-based approaches to identify novel cell surface markers which can be utilized for enrichment of stem cell derived alpha and beta cells. We found a specific cell surface marker which is detected on stem cell derived beta and alpha cells, but not in the unwanted cells. We have utilized this antibody to enrich the alpha and beta cells while efficiently eliminate unwanted cells. This resulted in SC-islets with 98% purity (beta and alpha cells), devoid of exocrine, ductal or enterochromaffin cells. Unexpectedly, we also found that elimination of the unwanted cells strikingly improved functionality of the islets, achieving more than 10-fold increased insulin release following glucose stimulation. This suggest that the unwanted cells are not only a potential risk but also exhibit a negative impact on the SC-islet function. To summarize, we have developed a method to generate pure and highly functional SC-islets for treatment of T1D.
Funding Source: Knut and Alice Wallenberg Foundation, Vinnova, StratRegen at Karolinska Institutet.
