Efficient transduction of pancreas tissue slices with genetically encoded calcium integrators.

This study combines live pancreas tissue slices with viral transduction of the Calcium Modulated Photoactivatable Ratiometric Integrator 2 (CaMPARI2) biosensor for high-throughput analysis of islet calcium secretagogue responses. A key challenge of the pancreas slice model has been efficient transgene delivery throughout the slice volume while maintaining viability and function. Here, we demonstrate a robust adenoviral gene delivery approach to transduce slices with CaMPARI2 and apply photoconverting light to permanently mark glucose-induced calcium activity across all islets. This approach demonstrates glucose responsive CaMPARI2 labeling that correlates with insulin secretion. Using this novel high-throughput approach, we examine the relationship between islet size and calcium response. Larger isolated islets exhibit greater CaMPARI2 photoconversion in high glucose, whereas no size-function correlation is observed in islets resident in live slices. We also observe that slices capture a substantially higher proportion of small islets than isolated islets. Integrating CaMPARI2 with live pancreas slice studies enables multiplexed analyses, linking functional readouts to spatial features.