Controlling Human Stem Cell‐Derived Islet Composition Using Magnetic Sorting

ABSTRACT Stem cell‐derived islets (SC‐islets) consist of multiple hormone‐producing cell types and offer a promising therapeutic avenue for treating type 1 diabetes (T1D). Currently, the composition of cell types generated within these SC‐islets cannot be controlled via soluble factors during this differentiation process and consist of off‐target cell types. In this study, we devised a magnetic‐activated cell sorting protocol to enrich SC‐islets for CD49a, a marker associated with functional insulin‐producing β cells. SC‐islets were generated from human pluripotent stem cells using an adherent differentiation protocol and then sorted and aggregated into islet‐like clusters to produce CD49a‐enriched, CD49a‐depleted, and unsorted SC‐islets. Single‐cell RNA sequencing (scRNA‐seq) and immunostaining revealed that CD49a‐enriched SC‐islets had higher proportions of β cells and improved transcriptional identity compared to other cell types. Functional assays demonstrated that CD49a‐enriched SC‐islets exhibited enhanced glucose‐stimulated insulin secretion both In vitro and In Vivo following transplantation into diabetic mice. These findings suggest that CD49a‐based sorting significantly improves β cell identity and the overall function of SC‐islets, improving their effectiveness for T1D cell replacement therapies.