Measurement of Real-Time Serotonin Dynamics from Human-Derived Gut Organoids

Area of Science:

• Neurogastroenterology
• Stem Cell Biology
• Electrochemical Biosensing

Background:

• The gut-brain-immune axis is crucial for health, with serotonin as a key signaling molecule.
• The gut produces most of the body's serotonin, but studying its dynamics in humans is difficult.
• Human stem cell-derived organoids offer a controlled in vitro system for studying gut signaling.

Purpose of the Study:

• To develop and validate a human gut organoid model for real-time serotonin measurement.
• To investigate serotonin release dynamics in an enterochromaffin cell (ECC)-enriched gut organoid.
• To establish a novel platform for future research on gut serotonin and drug target identification.

Main Methods:

• Characterization of stem cell-derived gut organoids for enterochromaffin cell enrichment.
• Optimization of an in vitro buffer for cell viability and fast-scan cyclic voltammetry (FSCV) measurements.
• Real-time detection and quantification of serotonin release using FSCV, including response to forskolin (FSK) and 3-isobutyl-1-methylxanthine (IBMX) stimulation.

Main Results:

• Successfully enriched gut organoids with enterochromaffin cells, the primary serotonin producers.
• Detected spontaneous serotonin release events in vitro, which were enhanced by FSK/IBMX stimulation.
• Confirmed the measured signal as serotonin by demonstrating delayed reuptake in the presence of a selective serotonin reuptake inhibitor (SSRI).

Conclusions:

• This study presents the first real-time measurement of serotonin signaling in a human-derived gut organoid model.
• The developed model provides a powerful tool for investigating serotonin's role in gut physiology and pathophysiology.
• This platform is expected to accelerate the identification of novel therapeutic targets for gut-related disorders.