Single cell glucose-stimulated insulin secretion assay using nanowell-in-microwell plates

Area of Science:

• Cell Biology
• Endocrinology
• Biotechnology

Background:

• Pancreatic beta cells are crucial for regulating blood glucose by secreting insulin.
• Stem cell-derived beta (SCβ) cells are a promising source for diabetes research but often lack the insulin secretion levels of natural beta cells.
• Understanding functional heterogeneity is key to improving SCβ cell therapies.

Purpose of the Study:

• To develop a novel assay for measuring glucose-stimulated insulin secretion (GSIS) at the single-cell level.
• To investigate the functional heterogeneity of SCβ cells and donor-derived islet cells.
• To identify potential 'elite' cells responsible for high insulin output.

Main Methods:

• Development of a single-cell GSIS assay using open-top nanowells and insulin capture microbeads.
• Fabrication of nanowells on glass-bottom imaging microwell plates for quantitative microscopy.
• Measurement of insulin secretion from individual SCβ cells and donor islet cells under varying glucose concentrations.

Main Results:

• The assay successfully measured single-cell GSIS in both SCβ cells and donor-derived islet cells.
• Significant heterogeneity in insulin secretion was observed within both cell populations.
• A small subpopulation of 'elite' cells (<20%) was found to produce the majority (55-78%) of the secreted insulin.

Conclusions:

• The developed nanowell-based assay provides a sensitive and flexible platform for single-cell GSIS analysis.
• Functional heterogeneity is a critical characteristic of both stem cell-derived and donor-derived pancreatic beta cells.
• Identifying and understanding 'elite' insulin-producing cells could inform strategies for improving beta cell replacement therapies for diabetes.