Single-cell transcriptome profiling of pancreatic islets from early diabetic mice identifies Anxa10 for Ca2+ allostasis toward β-cell failure

Type 2 diabetes (T2D) is a progressive disorder denoted by hyperglycemia and impaired insulin secretion. Although a decrease in β-cell function and mass is a well-known trigger for diabetes, the comprehensive mechanism is still unidentified. Here we carried out single-cell RNA sequencing (scRNA-seq) of pancreatic islets from prediabetic and diabetic db/db mice, an animal model of T2D. We discovered a diabetes-specific transcriptome landscape of endocrine and nonendocrine cell types with subpopulations of β and α cells. We recognized a new prediabetic gene, Anxa10, that was induced by, and regulated Ca2+ influx from metabolic stresses. Anxa10-overexpressed β cells displayed suppression of glucose-stimulated intracellular Ca2+ elevation and potassium-induced insulin secretion. Pseudotime analysis of β cells predicted this Ca2+-surge responder-cluster proceeded to mitochondria dysfunction and also endoplasmic reticulum stress. Other trajectories comprised dedifferentiation and transdifferentiation, emphasizing acinar-like cells in diabetic islets. Altogether, our data provides a new insight into Ca2+ allostasis and β cell failure processes.