Fig. 6: Real-time control of blood glucose homeostasis by grazoprevir-inducible insulin exocytosis in type-1 diabetic mice.

A Principles of a StimExoINS-mediated cell therapy. Pancreatic host cells stably transgenic for StimExo and insulin expression (StimExoINS) are encapsulated into semipermeable alginate-poly-L-lysine-alginate beads and implanted into type-1 diabetic mice. Insulin exocytosis triggered by grazoprevir administration enables instant regulation of blood glucose levels. B, C Kinetics of grazoprevir-triggered insulin exocytosis in monoclonal StimExoINS cells. D Kinetics of calcium-dependent insulin exocytosis. E, F Grazoprevir-triggered exocytosis in microencapsulated StimExoINS cells. Same volume of alginate microbeads containing monoclonal 2-E8 cells generated with poly-L-lysine (PLK) of different molecular weight (MW) were seeded in 1 mL serum-free RPMI medium (vehicle control) or RPMI medium containing 0.5 µM Grazoprevir before NanoLuc levels in culture supernatants were profiled at different timepoints (E). insulin levels of PLK (MW:2000) microbeads were also quantified at different timepoints (F). Data in (B–F) are presented as the mean ± SEM, n = 3 independent experiments. Error bar=SEM. G Quantification of grazoprevir-inducible exocytosis in vivo. One day after implantation of 5 × 10⁶ microencapsulated 2-E8 cells into 8-week healthy wildtype C57/BL6J male mice, animals received different doses of grazoprevir solutions via intraperitoneal injection. NanoLuc production in the bloodstream was measured every 30 min. H Real-time glycemic control by grazoprevir-triggered insulin exocytosis in diabetic mice. 1 day after intraperitoneal implantation of 1 × 10⁷ microencapsulated StimExoINS or ElectroBeta into T1DM mice, mice were fasted for 4 h and received single injections of 200 µL saline (vehicle control) or grazoprevir (1 mg/kg) before glycemic levels were followed over 120 min. T1DM mice receiving grazoprevir but no cell implants were used as negative controls. Homeostatic blood glucose levels (5-10 mM) are marked with a transparent red box. Data in (G, H) are presented as the mean ± SEM; n = 4 mice per group, Error bar = SEM. Two-tailed unpaired Student t-tests were used to evaluate the statistical significance of differences between two groups. P-values more than 0.05 were considered statistically not significant. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. Source data are provided as a Source Data file.