Corneocyte lipid envelope (CLE), the key structure for skin barrier function and ichthyosis pathogenesis

Area of Science:

• Dermatology
• Genetics
• Biochemistry

Background:

• Ichthyosis research has identified numerous causative genes and molecules.
• Defects in the stratum corneum's barrier function are central to ichthyosis pathogenesis.
• Specific genes are crucial for forming the corneocyte lipid envelope (CLE), vital for skin barrier integrity.

Purpose of the Study:

• To review the synthesis, metabolism, and transport of epidermal ceramides, focusing on ultra-long-chain (ULC) acylceramides and CLE formation.
• To summarize ichthyosis and ichthyosis syndrome pathogeneses related to abnormal ULC-acylceramide synthesis and CLE malformation.

Main Methods:

• Literature review focusing on genetic abnormalities and pathogenetic processes in ichthyoses.
• Analysis of the role of specific genes (e.g., ABCA12, ALOXE3) in corneocyte lipid envelope (CLE) formation.
• Examination of ceramide synthesis, metabolism, and transport in epidermal tissues.

Main Results:

• Several ichthyosis-causative genes are directly involved in the formation of the CLE, which is primarily composed of ULC-ceramides.
• Abnormal synthesis of ULC-acylceramide and malformation of the CLE are significant factors in ichthyosis pathogenesis.
• Research on ichthyosis mechanisms has advanced understanding of epidermal ceramide dynamics.

Conclusions:

• Understanding epidermal ceramide biology and ichthyosis pathogenesis offers potential for developing novel therapies.
• The CLE, formed by ULC-ceramides, is a critical structure whose defects lead to ichthyosis phenotypes.
• Continued investigation into these pathways promises future therapeutic strategies for ichthyosis patients.