Norepinephrine and Serotonin Can Modulate the Behavior of the Probiotic Enterococcus faecium NCIMB10415 towards the...

Area of Science:

• Microbiology
• Neurogastroenterology
• Immunology

Background:

• The human gut microbiota and host engage in bidirectional signaling.
• Neurotransmitters like norepinephrine (NE) and serotonin (5HT) are abundant in the gut.
• Understanding microbial responses to these neurochemicals is crucial for gut health.

Purpose of the Study:

• To investigate the effects of NE and 5HT on the probiotic Enterococcus faecium NCIMB10415 (E. faecium SF68).
• To analyze E. faecium SF68's phenotypic and interactive responses to these neuroactive molecules.
• To explore the potential mechanisms of neurochemical sensing by E. faecium SF68.

Main Methods:

• Treatment of E. faecium SF68 with NE and 5HT.
• Assessment of biofilm formation (Confocal Laser Scanning Microscopy).
• Evaluation of adhesion to Caco-2/TC7 cells and epithelial barrier function (Transepithelial Electrical Resistance).
• Analysis of dendritic cell (DC) maturation, differentiation, and cytokine production.
• In silico and in vitro investigation of a putative hormone sensor.

Main Results:

• NE and 5HT treatments significantly increased biofilm formation and adhesion.
• Hormone treatments improved epithelial barrier function.
• No significant differences in DC differentiation or maturation were observed.
• NE-treated bacteria showed enhanced TNF-α production.
• Evidence suggests a bacterial two-component system senses 5HT and NE.

Conclusions:

• E. faecium SF68 can sense and respond to both NE and 5HT.
• These neurochemicals modulate E. faecium SF68's interaction with the host.
• A bacterial sensor system for gut neurochemicals is supported.
• This highlights a direct communication axis between the gut microbiota and the host nervous system.