XIAP Deficiency Impairs Colonic Tuft Cell Development and Predisposes to Crohn's Disease.

Area of Science:

• Immunology
• Gastroenterology
• Cell Biology

Background:

• X-linked inhibitor of apoptosis (XIAP) deficiency is linked to severe, refractory Crohn's disease (CD).
• Current curative options like hematopoietic stem cell transplantation (HSCT) have suboptimal outcomes.
• Novel therapeutic targets are needed for XIAP-deficient CD patients.

Purpose of the Study:

• To investigate the role of tuft cells in XIAP-deficient CD.
• To explore JAK inhibition as a therapeutic strategy for XIAP-deficient CD.

Main Methods:

• Analysis of tuft cell abundance in XIAP-deficient CD patients and Xiap knockout mice.
• Mechanistic studies involving TLE4 ubiquitination and Wnt/β-catenin-ASCL2 signaling.
• Assessment of JAK inhibition effects on tuft cell regeneration and inflammation in mice.
• Clinical observation of JAK1 inhibitor treatment in an XIAP-deficient CD patient.

Main Results:

• Reduced tuft cell abundance was observed in XIAP-deficient CD patients and Xiap knockout mice.
• XIAP deficiency leads to decreased TLE4 ubiquitination, increased TLE4 levels, and suppressed Wnt/β-catenin-ASCL2 signaling, impairing secretory lineage differentiation.
• Tuft cell deficiency contributes to intestinal inflammation in XIAP deficiency.
• JAK inhibition promoted tuft cell regeneration and reduced mucosal inflammation in Xiap knockout mice.
• JAK1 inhibitor treatment in an XIAP-deficient CD patient increased tuft cells and improved colonic symptoms.

Conclusions:

• Tuft cell deficiency is a key factor in the intestinal pathology of XIAP-deficient Crohn's disease.
• JAK inhibition represents a promising therapeutic approach for XIAP-deficient CD by promoting tuft cell regeneration and reducing inflammation.