The Pathophysiology of Farnesoid X Receptor (FXR) in the GI Tract: Inflammation, Barrier Function and Innate Immunity

Area of Science:

• Gastroenterology and Hepatology
• Molecular Biology
• Immunology

Background:

• The Farnesoid-X Receptor (FXR) is a nuclear receptor primarily known for its role in bile acid homeostasis in the liver.
• Emerging evidence highlights FXR's significant functions beyond the liver, particularly within the gastrointestinal tract.
• FXR is expressed in the intestine and implicated in regulating inflammation, epithelial barrier function, and immune responses.

Purpose of the Study:

• To review the current understanding of FXR's role in the gastrointestinal tract.
• To specifically examine FXR's involvement in intestinal inflammation, barrier function, and immune regulation.
• To identify areas of controversy and highlight the need for further research into FXR physiology.

Main Methods:

• This review synthesizes findings from existing scientific literature.
• It analyzes studies investigating FXR's physiological roles in the GI tract.
• The review discusses data from various model systems to explore FXR's complex functions.

Main Results:

• FXR is increasingly recognized for its critical roles in intestinal health, including modulating inflammation and maintaining barrier integrity.
• Data suggests FXR influences the gut immune system, though its precise mechanisms are still being elucidated.
• Conflicting results exist across different model systems, indicating a complex and context-dependent role for FXR.

Conclusions:

• FXR is a significant modulator of intestinal physiology with implications for gastrointestinal health and disease.
• Further research is needed to clarify the complex roles of FXR in the GI tract and resolve conflicting data.
• A deeper understanding of FXR physiology is essential for the translational application of FXR-targeted therapies in human GI pathologies.