mTORC1 in the Paneth cell niche couples intestinal stem-cell function to calorie intake

Area of Science:

• Stem cell biology
• Nutritional physiology
• Gastrointestinal research

Background:

• The response of adult stem and niche cells to nutritional status is poorly understood.
• Paneth cells are crucial components of the intestinal stem cell (ISC) niche.

Purpose of the Study:

• To investigate how Paneth cells modulate ISC function under calorie restriction.
• To elucidate the molecular mechanisms linking nutritional state, Paneth cells, and ISC self-renewal.

Main Methods:

• Investigated the role of mechanistic target of rapamycin complex 1 (mTORC1) signaling in Paneth cells during calorie restriction.
• Utilized rapamycin to mimic calorie restriction effects and assess ISC function.
• Examined the expression and function of bone stromal antigen 1 (Bst1) in Paneth cells.

Main Results:

• Calorie restriction augments ISC function by reducing mTORC1 signaling in Paneth cells.
• Rapamycin treatment mimics the ISC-enhancing effects of calorie restriction.
• mTORC1 regulation in Paneth cells, not ISCs, is key; forced mTORC1 activation in Paneth cells blocks calorie restriction benefits.
• Increased Bst1 expression in Paneth cells mediates calorie restriction and rapamycin effects on ISC function.

Conclusions:

• mTORC1 signaling in Paneth cells non-cell-autonomously regulates ISC self-renewal.
• The intestinal niche plays a vital role in integrating organismal physiology with stem cell function.