E-cadherin interactions are required for Langerhans cell differentiation

Area of Science:

• Immunology
• Dermatology
• Cell Biology

Background:

• Human skin harbors two distinct dendritic cell (DC) subsets: epidermal Langerhans cells (LCs) and dermal DCs.
• LCs express Langerin and are found in the epidermis, while dermal DCs express DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and reside in the dermis.
• The role of epidermal localization in LC differentiation remains unclear.

Purpose of the Study:

• To investigate the role of E-cadherin, expressed by epidermal keratinocytes (KCs), in the differentiation of LCs.
• To determine if E-cadherin provides environmental cues for LC differentiation within the epidermis.

Main Methods:

• Monocytes were differentiated into LC-like cells using IL-4, GM-CSF, and TGF-β1.
• LC-like cells were co-cultured with keratinocytes expressing E-cadherin or with recombinant E-cadherin.
• The expression of Langerin and DC-SIGN was analyzed in LC-like cells.
• LC-like cells were pretreated with an anti-E-cadherin antibody to assess the necessity of E-cadherin interactions.

Main Results:

• Monocyte-derived LC-like cells expressed both Langerin and DC-SIGN.
• Co-culture with E-cadherin-expressing KCs or recombinant E-cadherin reduced DC-SIGN expression and induced an LC phenotype.
• Anti-E-cadherin antibody treatment abolished Langerin expression, highlighting the importance of E-cadherin interactions for LC differentiation.

Conclusions:

• E-cadherin expressed by epidermal keratinocytes is crucial for the differentiation of Langerhans cells.
• E-cadherin provides essential environmental cues within the epidermis that promote LC differentiation.
• These findings elucidate a key mechanism regulating the development of epidermal LCs.