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

This study combines live pancreas tissue slices with adenoviral transduction of the Calcium Modulated Photoactivatable Ratiometric Integrator 2 (CaMPARI2) biosensor for high-throughput analysis of islet calcium responses. Pancreas slices preserve islets within their native microenvironment, adding tissue context to the study of islet function and pathology. A key challenge of the pancreas slice model has been efficient transgene delivery while maintaining viability and function. Here, we demonstrate a robust adenoviral gene delivery approach using targeted and universal promoters. By transducing slices with CaMPARI2 and applying 405 nm photoconverting light, we permanently marked glucose-induced calcium activity across entire islet populations while preserving the in situ tissue context. Applied to nPOD donor tissues, including from individuals with type 1 diabetes, type 2 diabetes, and non-diabetic controls, this approach demonstrated glucose responsive CaMPARI2 labeling that correlated with insulin secretion. Integrating CaMPARI2 with pancreas slices enables multiplexed analyses, linking a functional readout with spatial context through immunostaining or gene expression to advance understanding of human islet behavior.