MedicalResearch.com Interview with: Akio Kihara, PhD. Laboratory of Biochemistry Faculty of Pharmaceutical Sciences, Hokkaido University Sapporo, Japan MedicalResearch.com: What is the background for this study? What are the main findings? Response: The skin barrier is the most powerful defensive mechanism terrestrial animals possess against pathogens and harmful substances such as allergens and pollutants. Recent studies indicate that lipids play a central role in skin barrier formation. Multi-lamellar structures consisting of lipids are formed extracellularly in the stratum corneum, the outermost layer of epidermis, and their high hydrophobicity prevents the invasion of external pathogens and compounds. The stratum corneum-specific lipid acylceramide is especially important for skin barrier formation. Decreases in acylceramide levels are associated with cutaneous disorders such as ichthyosis and atopic dermatitis. However, the mechanism behind acylceramide production is poorly understood, especially regarding the last step of acylceramide production: i.e., esterification of ω-hydroxyceramide with linoleic acid. This means that the broader picture of the molecular mechanisms behind skin barrier formation still remained unclear. Although PNPLA1 has been identified as an ichthyosis-causative gene, its function in skin barrier formation remains unresolved. In the present study, we revealed that PNPLA1 catalyzes the last step of acylceramide synthesis. Our finding completes our knowledge of the entire pathway of the acylceramide production, providing important insights into the molecular mechanisms of skin barrier formation. (more…)