Visual quantification of prostaglandin E₂ discharge from a single cell

Area of Science:

• Cellular biology
• Biochemistry
• Physiology

Background:

• Calcium transients are known to stimulate prostaglandin E2 (PGE2) secretion.
• Understanding the quantitative aspects of intercellular communication mediated by PGE2 is crucial for various physiological processes.

Purpose of the Study:

• To visualize and quantify prostaglandin E2 (PGE2) secretion from single cells.
• To measure protein kinase A (PKA) activation in response to PGE2.
• To investigate the spatial dynamics of PGE2-mediated intercellular communication.

Main Methods:

• Development of genetically engineered cells for optogenetic/chemogenetic calcium channel stimulation.
• Utilized Förster resonance energy transfer (FRET)-based biosensors for PKA activation.
• Combined fluorescence microscopy with a diffusion-based simulation model for quantification.

Main Results:

• Successfully visualized PGE2-induced PKA activation and quantified PGE2 secretion.
• Demonstrated that a single calcium transient can activate PKA in over 1000 neighboring cells.
• Estimated a single HeLa cell secretes 0.25 fmol of PGE2 per calcium transient.

Conclusions:

• The developed method allows for quantitative visualization of single-cell PGE2 secretion and its impact on neighboring cells.
• PGE2 discharge rate is comparable to its diffusion rate, influencing intercellular communication.
• This study provides a quantitative framework for understanding calcium-driven intercellular signaling via PGE2.