Summary
Inducing β-cell proliferation could inhibit diabetes progression. Many factors have been suggested as potential β-cell mitogens, but their impact on β-cell replication has not been confirmed due to the lack of a standardized β-cell proliferation assay. In this study, we developed a novel method that specifically labels replicating β cells and yields more reproducible results than current immunohistochemical assays. We established a mouse line expressing the fluorescent ubiquitination-based cell cycle indicator (Fucci2a) reporter only in β cells through Cre-mediated recombination under the control of the rat insulin promoter (RIP-Cre;Fucci2aR). Three-dimensional imaging of optically cleared pancreas tissue from these mice enabled the quantification of replicating β cells in islets and morphometric analysis of islets following mitogen treatment. Intravital imaging of RIP-Cre;Fucci2aR mice revealed cell cycle progression of β cells. Thus, this novel mouse line is a powerful tool for spatiotemporal analysis of β-cell proliferation in response to mitogen stimulation.
