Follicular epithelium and stratum corneum keratinocyte proteins and lipids

The follicular epithelium and stratum corneum keratinocyte proteins and lipids constitute the primary structural and functional barrier of the skin and the lining of the pilosebaceous unit. The stratum corneum is composed of keratin-rich corneocytes surrounded by a lipid matrix of ceramides, cholesterol, and free fatty acids, which together regulate hydration and protect against pathogens (StatPearls: Physiology, Stratum Corneum, 2023). The follicular epithelium is a specialized region where abnormal keratinization can lead to the obstruction of the hair follicle, a key step in the pathogenesis of acne vulgaris (PubMed: Adapalene: a retinoid-like compound for the treatment of acne, 1997). Drugs such as topical retinoids (e.g., adapalene) target these components by binding to nuclear retinoic acid receptors within keratinocytes, subsequently altering the expression of proteins involved in differentiation and desquamation (NIH: The Skin Barrier, 2022). This process normalizes the shedding of cells within the follicle, preventing the formation of microcomedones and reducing inflammatory lesions. Additionally, therapeutic lipids are used to restore the barrier function in inflammatory skin diseases like atopic dermatitis (Journal of Clinical and Aesthetic Dermatology: The Role of Ceramides in Skin Health, 2014). While clinically significant, this target is a complex anatomical and biochemical assembly rather than a single molecular entity.

Other names

Skin barrierPilosebaceous unit componentsEpidermal barrier proteins and lipidsFollicular epithelial barrier

Normalization of keratinocyte differentiation and desquamation within the hair follicle and on the skin surface, and restoration of the lipid barrier.