These mechanisms, described in vivo in mice, engage molecule CD98hc, which is involved in epidermis renewal and could be an indicator of the skin's capacity for regeneration.
The results were published in the Journal of Experimental Medicine review.
The epidermis, the surface layer of the skin, is mainly composed of keratinocytes cells, which, in humans, are renewed continuously over a 21-day cycle. These cells are located on a membrane made up of components from the extracellular matrix that provides the junction with the dermis, the deep layer of the skin (see diagram). The epidermis is renewed by cell proliferation and diferentiation that maintains the balance of adult tissues. This balance, known as "homeostasis", is essential for tissues to function correctly and any alterations to it are responsible for the physical changes associated with aging: sagging skin due to reduced skin cell proliferation, wound healing defects, loss of hair, etc.
The ATIP-Avenir team "Epidermal homeostasis and tumorigenesis" directed by Inserm researcher Chlo- F-ral, studied the numerous cellular factors involved in maintaining this balance. Particular attention was paid to CD98hc, a molecule known for its interaction with receptors that cause skin aging. With age, the activity of the transporter CD98hc and integrins (the receptors connected to the components in the extra cellular matrix) is disturbed. However, until now the mechanisms involved had never been identified.