Human intelectin-2 (ITLN2) is selectively expressed by secretory Paneth cells

Area of Science:

• Gastroenterology
• Molecular Biology
• Human Genetics

Background:

• Intelectins are conserved proteins implicated in human diseases like Crohn's disease (CD).
• The human genome encodes two intelectin genes: intelectin-1 (ITLN1) and intelectin-2 (ITLN2).
• Limited information exists regarding ITLN2's structure, function, and role in intestinal diseases.

Purpose of the Study:

• To characterize the structure and expression of intelectin-2 (ITLN2).
• To investigate the role of ITLN2 in the context of inflammatory bowel diseases, specifically Crohn's disease (CD) and ulcerative colitis (UC).

Main Methods:

• Comparative analysis of ITLN1 and ITLN2 primary structures.
• Localization studies of ITLN2 in Paneth cells and intestinal tissues.
• Quantitative analysis of ITLN2 mRNA levels in surgical specimens from CD, UC, and control patients.

Main Results:

• ITLN2 exhibits unique structural features compared to ITLN1, including a distinct amino terminus and altered glycan-binding residues.
• ITLN2 is a highly abundant, Paneth cell-specific protein, stored in secretory granules and existing as a multimer in the small intestine.
• ITLN2 mRNA levels were significantly reduced in the ileum of CD patients.
• ITLN2 expression was undetectable in healthy colon but present in metaplastic Paneth cells in colonic CD and UC.

Conclusions:

• ITLN2 possesses distinct structural and localization characteristics compared to ITLN1.
• Reduced ITLN2 expression in the ileum suggests a potential role in Crohn's disease pathogenesis.
• Altered ITLN2 expression in metaplastic Paneth cells in the colon indicates a possible involvement in colonic inflammatory bowel disease.
• Further research is warranted to elucidate the specific functions of ITLN2 in intestinal health and disease.