Gut-liver axis calibrates intestinal stem cell fitness

Area of Science:

• Gastroenterology
• Hepatology
• Stem Cell Biology

Background:

• The gut-liver axis is crucial for physiological regulation, but its role in intestinal homeostasis is not fully understood.
• Intestinal stem cells (ISCs) are vital for gut tissue maintenance and repair, regulated by complex signaling pathways.
• Liver-derived factors can influence gut function, highlighting the importance of inter-organ communication.

Purpose of the Study:

• To elucidate the mechanisms by which the gut-liver axis regulates intestinal physiology, specifically focusing on intestinal stem cell behavior.
• To identify key molecular mediators involved in the communication between the liver and the intestine.
• To understand how liver-derived factors influence ISC proliferation and gut homeostasis.

Main Methods:

• Hepatectomy in mice to investigate liver-gut interactions.
• Transcriptomic and proteomic profiling to identify key signaling molecules.
• Analysis of the Wnt/β-catenin signaling pathway in intestinal stem cells.
• Pharmacological manipulation using peroxisome proliferator-activated receptor-α (PPARα) agonists.

Main Results:

• Pigment epithelium-derived factor (PEDF), a liver-secreted Wnt inhibitor, was identified as a key regulator of ISC proliferation.
• PEDF restrains ISC hyperproliferation, maintaining gut homeostasis by suppressing the Wnt/β-catenin pathway.
• Intestinal inflammation triggers liver sensing of microbial danger signals, leading to decreased PEDF production via PPARα.
• Reduced PEDF liberates ISC proliferation, promoting intestinal tissue repair.
• Fenofibrate, a PPARα agonist, increased colitis susceptibility by enhancing PEDF activity.

Conclusions:

• Pigment epithelium-derived factor (PEDF) plays a critical role in maintaining intestinal homeostasis by controlling ISC expansion.
• The liver senses intestinal inflammation and modulates PEDF production, influencing gut repair mechanisms.
• Reciprocal communication between the gut and liver, mediated by PEDF, is essential for calibrating ISC proliferation and gut health.