Improve cellular fitness of human stem cell-derived islets under hypoxia

Stem cell-derived islet (SC-islet) cell therapy holds immense potential for the treatment of Type 1 Diabetes. However, low oxygen supply leads to cell dysfunction post-transplantation, especially in subcutaneous spaces and encapsulation devices. The response of SC-islets to hypoxia and effective strategies to alleviate its detrimental effects remain poorly understood. This study investigates the impact of hypoxia on SC-islets and elucidate the dynamics of hypoxia-induced stress. We performed transcriptional profiling of human SC-islets exposed to hypoxic conditions, and drew the transcriptomic and epigenetic profiles of single cells. Our findings demonstrate that β cells within SC-islets gradually undergo a decline in cell identity and metabolic function in response to hypoxia. The loss of expression from immediate early genes, specifically EGR1, FOS, and JUN, results in the downregulation of key transcription factors (TFs) that are essential for maintaining SC-islet cell identity under hypoxic conditions. By comparing SC-islets under low and high oxygen conditions, we identified genes that play a role in maintaining the fitness of SC-islets in a low-oxygen environment. Notably, the expression of EDN3, a potent vasoconstrictor gene that is enriched in native pancreatic β cells, significantly aids in preserving β cell identity under hypoxic conditions. Elevated expression of EDN3 in SC-islets effectively mitigated the deleterious effects of hypoxia by modulating genes involved in SC-islet maturation including genes associated with glucose sensing and regulation in β cells. These insights improve the understanding of SC-islets under hypoxic conditions, offering a potential point of intervention for future clinical applications in the treatment of Type 1 Diabetes