keratinocytdifferentiering

Keratinocyte differentiation is a complex biological process occurring in the epidermis, the outermost layer of the skin. It describes the maturation of keratinocytes, the primary cells of the epidermis, as they migrate from the basal layer upwards towards the surface. This journey involves a series of molecular and structural changes that ultimately result in the formation of a protective barrier. In the basal layer, keratinocytes are actively dividing and undifferentiated. As they begin to ascend into the suprabasal layers, they initiate a program of differentiation. This program involves the synthesis of specific proteins, most notably keratins, which are structural proteins that form intermediate filaments within the cells. As differentiation progresses, keratinocytes flatten, lose their nuclei and organelles, and accumulate increasing amounts of keratin. This process culminates in the formation of the stratum corneum, the outermost layer of the epidermis, composed of dead, flattened keratinocytes called corneocytes. These corneocytes are enucleated and filled with keratin, providing mechanical strength and a barrier against environmental insults, pathogens, and water loss. The differentiation process is tightly regulated by a complex interplay of signaling pathways and transcription factors.