Galectin-3 promotes sialyl Lewis X epitope biosynthesis in monocytes

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Monocytes are crucial for inflammatory responses and tissue repair.
• Monocyte recruitment to injury sites involves selectin-mediated adhesion.
• Galectin-3 is implicated in monocyte recruitment, but its precise role is unclear.

Purpose of the Study:

• To elucidate the mechanism by which galectin-3 enhances monocyte recruitment.
• To investigate galectin-3's effect on sialyl Lewis X (sLeX) expression on monocytes.

Main Methods:

• Utilized genetic and pharmacological inhibition of galectin-3 in mouse and human monocytes.
• Assessed sLeX epitope biosynthesis and α(1,3)-fucosyltransferase 7 (FUT7) expression.
• Restored FUT7 activity in galectin-3-deficient monocytes to evaluate rescue effects.

Main Results:

• Galectin-3 significantly enhances sLeX epitope biosynthesis in monocytes.
• This enhancement is mediated by the transcriptional upregulation of FUT7, a key enzyme in sLeX synthesis.
• Restoring FUT7 activity rescues sLeX expression on galectin-3-deficient monocytes.

Conclusions:

• Galectin-3 plays a novel role in regulating monocyte adhesion.
• It directly influences selectin ligand biosynthesis by upregulating FUT7 and consequently sLeX expression.
• This mechanism provides new insights into inflammatory cell trafficking.