Identification of a Quorum Sensing-Dependent Communication Pathway Mediating Bacteria-Gut-Brain Cross Talk

Area of Science:

• Microbiology
• Neuroscience
• Gastroenterology

Background:

• The gut microbiome significantly impacts human health and disease.
• Communication pathways between gut bacteria and the host, particularly via the gut-brain axis, are not fully understood.

Purpose of the Study:

• To investigate if intestinal neurons can directly sense bacteria.
• To identify bacterial mediators involved in gut-brain communication.
• To understand how these mediators affect neuronal function and intestinal physiology.

Main Methods:

• Utilized supernatants from Staphylococcus aureus cultures.
• Examined effects on extrinsic sensory afferent nerves and cultured sensory neurons.
• Assessed changes in intestinal motility and secretion.
• Employed genetic manipulation of S. aureus to identify key bacterial factors.

Main Results:

• Bacterial mediators from S. aureus at high population density induced a biphasic response in sensory nerves.
• These mediators increased sensory neuron membrane permeability.
• Bacterial pore-forming toxins, regulated by quorum sensing, were identified as key mediators.
• These toxins differentially modulate sensory nerve activity (excitation and inhibition).

Conclusions:

• Intestinal neurons possess the ability to sense bacteria independently of the immune system.
• Bacterial mediators, specifically quorum sensing-regulated toxins, directly modulate gut-brain communication.
• These bacterial-host interactions can influence intestinal symptoms, reflex function, and potentially host behavior and homeostasis.