Enhanced serotonin signaling increases intestinal neuroplasticity

Area of Science:

• Gastroenterology
• Neuroscience
• Cell Biology

Background:

• Intestinal mucosa regeneration involves accelerated enterocyte proliferation and villus growth, crucial for recovery after injury or resection.
• Serotonin (5-HT) is recognized for regulating mucosal homeostasis and epithelial growth.
• The specific impact of 5-HT on other villus components during growth remains largely unexplored.

Purpose of the Study:

• To investigate the hypothesis that 5-HT-stimulated intestinal epithelial growth is associated with concurrent growth in other villus structures, specifically enteric neural axonal processes.
• To elucidate the role of serotonin signaling in intestinal mucosal growth and neuronal plasticity.

Main Methods:

• Utilized serotonin reuptake transporter knockout (SERTKO) mice and selective serotonin reuptake inhibitors (SSRI) in wild-type mice to enhance serotonergic signaling.
• Administered 4-chloro-L-phenylalanine (PCPA) to inhibit 5-HT synthesis.
• Assessed intestinal segments for villus height, crypt depth, crypt proliferation, and Gap 43 expression (a neuroplasticity marker) via immunofluorescence and Western blot.

Main Results:

• SERTKO and WT-SSRI mice exhibited significantly increased villus height, crypt depth, and enterocyte proliferation compared to wild-type controls.
• Gap 43 expression, indicative of neuroplasticity, was markedly elevated in enhanced serotonin signaling models.
• Inhibition of 5-HT synthesis with PCPA reversed the observed increases in both mucosal growth and Gap 43 expression.

Conclusions:

• Elevated serotonin signaling drives intestinal mucosal growth, impacting both epithelial cells and the enteric nervous system.
• Serotonin (5-HT) is a critical regulator of intestinal mucosal growth and neuronal plasticity.
• The findings underscore the dual role of 5-HT in gut epithelial and neural development.