Canonical human blood dendritic cells are distinguished by robust E-selectin binding

Area of Science:

• Immunology
• Cell Biology
• Glycobiology

Background:

• Leukocyte extravasation is crucial for immune surveillance and inflammatory responses.
• E-selectin-mediated adhesion, involving sialyl Lewis X (sLeX) ligands, facilitates cell migration from blood to tissues.
• Neutrophils and monocytes express E-selectin ligands, but dendritic cells' (DCs) capacity is unknown.

Purpose of the Study:

• To investigate whether human blood dendritic cells (DCs) express E-selectin ligands.
• To understand the molecular mechanisms underlying DC recruitment to tissues.

Main Methods:

• Multiparameter flow cytometry to assess E-selectin binding on DCs.
• Biochemical analyses to characterize adhesive properties.
• Transcriptomic analysis of glycosyltransferases involved in sLeX biosynthesis.

Main Results:

• All subsets of human blood DCs robustly bind to E-selectin.
• This E-selectin binding capacity is also present in DC precursors.
• Single-cell RNA sequencing provided limited insight into sLeX biosynthesis effectors in DCs.

Conclusions:

• Human blood DCs possess a unifying feature of E-selectin binding, crucial for their tissue recruitment.
• This convergent mechanism highlights DCs' role in bridging innate and adaptive immunity.
• Findings offer insights into DC migration in both steady-state and inflammatory conditions.