Gastrointestinal Neurons Expressing HCN4 Regulate Retrograde Peristalsis

Area of Science:

• Neuroscience
• Gastroenterology
• Zebrafish Genetics

Background:

• Peristalsis is crucial for gut function, with the enteric nervous system (ENS) regulating motility.
• While anterograde peristalsis is understood, the neural control of retrograde peristalsis remains unclear.

Purpose of the Study:

• To elucidate the neural mechanisms governing retrograde peristalsis.
• To identify specific neuronal populations and molecular targets involved in retrograde gut motility.

Main Methods:

• Forward genetics screen in zebrafish to identify genes regulating peristalsis.
• Pharmacological inhibition of hyperpolarization-activated nucleotide-gated (HCN) channels.
• Optogenetic activation of specific neuronal populations (HCN4+ neurons).
• Assessment of anterograde and retrograde peristalsis in zebrafish models.

Main Results:

• A specific population of enteric neurons expressing HCN4 was identified as critical for retrograde peristalsis.
• Inhibition of HCN4 channels significantly attenuated retrograde peristalsis.
• Optogenetic activation of HCN4+ neurons enhanced retrograde peristalsis without affecting anterograde peristalsis.
• HCN4+ neurons appear to transmit signals towards the oral end and influence local circular muscle circuits.

Conclusions:

• HCN4+ neurons in the ENS are key regulators of retrograde peristalsis.
• HCN4 channels represent a potential therapeutic target for modulating gut motility disorders.