Mathematical modeling of gap junction coupling and electrical activity in human β-cells

Area of Science:

• Endocrinology
• Computational Biology
• Cellular Electrophysiology

Background:

• Coordinated insulin secretion relies on electrical coupling of pancreatic beta-cells through connexin-36 gap junctions.
• While studied in mice, human beta-cell electrophysiology and coupling remain less understood.
• Human islets express connexin-36, indicating potential for electrical coupling.

Purpose of the Study:

• To theoretically investigate the gap junction coupling strength needed for synchronizing human beta-cell electrical activity.
• To compare theoretical findings with experimental data from human beta-cells.
• To explore how gap junction coupling influences different electrical activity patterns in human beta-cell clusters.

Main Methods:

• Utilized a recent mathematical model of human beta-cell electrophysiology.
• Simulated electrical activity in small clusters of human beta-cells.
• Estimated coupling strength from experimental patch clamp recordings.

Main Results:

• A minimum coupling strength of approximately 20 pS (2 pS pF(-1)) is required for synchronized spiking activity.
• Estimated human beta-cell coupling strength is 100-200 pS (10-20 pS pF(-1)), similar to mouse beta-cells.
• Electrical coupling prolongs rapid bursting and synchronizes slow bursting, especially when metabolic oscillators are in phase.

Conclusions:

• Realistic gap junction conductances are sufficient to synchronize small human beta-cell clusters.
• Findings support experimental observations of beta-cell synchrony in human islets.
• Highlights the need for further research into electrical coupling in human pancreatic islets.