Résumé de communication

Objectives: In this study, we examined whether application of tensing cosmetic products on the stratum corneum could trigger mechanical tension across skin layers, activate piezo-mediated mechanotransduction in keratinocytes and affect fibroblast activity and extracellular matrix remodeling in the dermis. Introduction: Human skin is a highly dynamic organ capable of sensing and responding to mechanical stimuli through tightly regulated communication between the epidermis and dermis. Mechanical forces can modulate skin structure and function via mechanotransduction pathways. Mechanosensitive Piezo channels are key receptors for this mechanotransduction as they convert mechanical tension into electrochemical signals. However, while the role of Piezo receptors in epidermal keratinocytes has been established, it remains unclear whether mechanical tension at the skin surface can influence deeper dermal response Materials / method: We applied a tensing cosmetic products on the stratum corneum of skin explants and to evaluate their effects, we used Atomic Force Microscopy (AFM), which enabled us to directly measure nanoscale changes in tension and surface topography not only at the stratum corneum but also within the epidermis and dermis. Piezo receptors activation and extracellular matrix proteins were then quantified through immunohistochemistry. Results: Following cosmetic application, we observed an activation of Piezo receptors as well as modulation of key extracellular matrix proteins, including, E-cadherin, and collagen III. AFM confirmed the generation of measurable mechanical forces at the skin surface and their transmission into deeper layers. These alterations suggest activation of downstream signaling pathways that may influence dermal fibroblasts. Conclusion: Our findings support the hypothesis that mechanical cues at the epidermal level, sensed via Piezo channels, can orchestrate interlayer communication leading to extracellular matrix remodeling in the dermis, highlighting a potential epidermis-to-dermis mechanotransduction axis in human skin.