Quantitative visualization of synchronized insulin secretion from 3D-cultured cells

Area of Science:

• Cell Biology
• Biochemistry
• Endocrinology

Background:

• Insulin secretion is crucial for glucose homeostasis.
• Understanding synchronized insulin release from pancreatic beta cells is vital for diabetes research.
• Current methods for visualizing dynamic insulin secretion are limited.

Purpose of the Study:

• To develop and validate a video-rate bioluminescence imaging method for quantitative visualization of synchronized insulin secretion.
• To establish a stable cell line expressing an insulin-luciferase fusion protein for real-time secretion monitoring.
• To investigate the effects of an antidiabetic drug on synchronized insulin secretion in 2D and 3D cell cultures.

Main Methods:

• Utilized video-rate bioluminescence imaging to capture dynamic insulin secretion.
• Created a rat INS-1E beta cell line (iGL) stably expressing an insulin-Gaussia luciferase (Insulin-GLase) fusion protein.
• Performed quantitative analysis of secreted Insulin-GLase using a luminometer.

Main Results:

• Achieved quantitative visualization of synchronized insulin secretion from isolated rat pancreatic islets and 3D-cultured beta cell spheroids.
• Observed completely synchronized oscillatory insulin secretion in iGL cell clusters in response to high glucose.
• Demonstrated the impact of glibenclamide on synchronized insulin secretion in both 2D and 3D iGL cell cultures.

Conclusions:

• The developed bioluminescence imaging method is effective for investigating protein secretion from living 3D-cultured cells.
• The iGL cell line serves as a valuable tool for real-time monitoring of insulin secretion.
• This platform is promising for evaluating the efficacy of antidiabetic drugs.