Laminin α5 in the Keratinocyte Basement Membrane Is Required for Epidermal–Dermal Intercommunication

The study investigated the role of laminin α5 in the epidermal basement membrane (BM) using a keratinocyte-specific knockout mouse model (Lama5Ker5). The absence of laminin α5 led to hyperproliferation of basal keratinocytes and delayed hair follicle development, with increased expression of dermally derived ECM molecules and immune cell infiltration. These changes were linked to altered expression of growth factors like KGF and EGF, affecting keratinocyte proliferation and hair follicle development. The findings suggested that laminin α5 played a crucial role in epidermal–dermal intercommunication, influencing skin homeostasis by modulating keratinocyte behavior and dermal responses.