(229bk) Regulation of Insulin Secretion in Pancreatic β-Cells with an Optogenetic Approach

Regulation of blood glucose is dependent on proper secretion of insulin by pancreatic β-cells. Cyclic AMP (cAMP) is a key activator of the release of hormone through the increase in Ca²⁺ influx via voltage-dependent channels. Optogenetics has been widely implemented to control biological processes with light. Here, we hypothesized that a photoactivatable adenylyl cyclase (PAC) can be employed to modulate intracellular cAMP in β-cells. To test this hypothesis, the PAC gene was delivered to cultured mouse insulinoma β-cells, which were subsequently illuminated with light and the levels of cAMP and secreted insulin were assessed under various conditions. The PAC gene was delivered with an adenoviral vector and its efficient expression were confirmed by western blot analysis and fluorescence microscopy. Various multiplicities of infection were screened to achieve high transduction efficiency without compromising cell viability. The level of cAMP peaked within 10 minutes of light stimulation and returned to baseline in less than 20 minutes after terminating illumination. A concomitant increase was observed in secreted insulin. The results demonstrate the potential of the optogenetic system described here for the precise and efficient control of insulin secretion by pancreatic β-cells and may facilitate the development of technologies for the treatment of metabolic diseases such as diabetes.