Real-time single-cell imaging of protein secretion

Area of Science:

• Cell Biology
• Immunology
• Biotechnology

Background:

• Protein secretion is crucial for intercellular communication but its dynamics at the single-cell level remain unclear due to population averaging.
• Intercellular heterogeneity obscures precise understanding of regulated protein secretion pathways.

Purpose of the Study:

• To develop a novel assay platform for real-time, single-cell resolution imaging of protein secretion.
• To investigate the heterogeneous onset of interleukin-1 beta (IL-1β) secretion from monocytes.
• To elucidate the chronological relationship between membrane integrity loss and IL-1β secretion.

Main Methods:

• Developed a novel assay platform using sandwich immunoassay and total internal reflection microscopy in sub-nanolitre microwell arrays.
• Enabled real-time imaging of protein secretion at 1-minute intervals.
• Monitored nonclassical IL-1β secretion from monocytes post-stimulation.

Main Results:

• Successfully detected heterogeneous onset times of IL-1β secretion at the single-cell level.
• Elucidated the chronological sequence linking membrane integrity loss to IL-1β secretion.
• Demonstrated the capability for simultaneous monitoring of protein secretion and intracellular events.

Conclusions:

• The developed platform provides unprecedented insight into single-cell protein secretion dynamics.
• This tool facilitates the study of intercellular heterogeneity in cellular signaling.
• It offers a powerful method for analyzing protein secretion alongside intracellular events in live cells.