Optical imaging and single-cell RNA sequencing reveal single-cell electrophysiological heterogeneity in pancreatic islets

Pancreatic islets maintain glucose homeostasis through coordinated electrical activity, yet how single-cell excitability varies within islets and contributes to collective function remains poorly understood. Here, we develop an optical approach that enables simultaneous measurement of plasma membrane potential and cytosolic Ca2+ dynamics across more than 1,300 individual dispersed pancreatic islet cells. Quantitative analysis revealed pronounced heterogeneity in electrical firing frequency and spike patterns that was not clearly explained by major cell-type differences. Model-based analysis of electrical and Ca2+ signals suggested that variability in membrane conductance and Ca2+ clearance contributes to differential cytosolic Ca2+ accumulation among cells. In pseudo-islet models, mixed cell populations exhibited a broader dynamic range of insulin secretion across low and high glucose conditions than expected from content-normalized monoclonal responses. Linking electrophysiological phenotypes with gene expression profiles, we further identified Clec4d as a candidate associated with electrical and Ca2+-handling heterogeneity. CLEC4D expression was reduced in islets from obese diabetic (ob/ob) mice and showed an exploratory decreasing trend with donor age in human islets. Together, these findings reveal intrinsic electrophysiological heterogeneity as a defining feature of islet organization and suggest its potential association with islet dysfunction in metabolic disease and aging.

This dataset include all processed data we mentioned in our paper, the code were uploaded on https://github.com/CullinanLi/heterogeneity-in-pancreatic-islet-cells, with the same folder name, if we missed anything, please feel free to contact the lead contact.