Chronological aging impacts abundance, function and microRNA content of extracellular vesicles produced by human epidermal keratinocytes.

The disturbance of intercellular communication is one of the hallmarks of aging. The goal of this study is to clarify the impact of chronological aging on extracellular vesicles (EVs), a key mode of communication in mammalian tissues. We focused on epidermal keratinocytes, the main cells of the outer protective layer of the skin which is strongly impaired in the skin of elderly.

Elastogenic potential and antisagging properties of a novel Murraya koenigii extract.

Background: The process by which functional elastic fibers are produced, namely elastogenesis, is complex and difficult to assess in vitro. Identifying efficient elasticity-boosting ingredients thus represents a challenge.

Aims: The elasticity-boosting properties of a novel extract of Murraya koenigii leafy stems were assessed in vitro in 3D culture models before being evaluated in human female volunteers.

Maintenance of Chronological Aging Features in Culture of Normal Human Dermal Fibroblasts from Old Donors.

Chronological aging is defined as a time-dependent decline of tissue homeostasis which severely impacts skin. Understanding the mechanisms of skin aging is an active research area limited by the lack of relevant in vitro models. Being a component of aging, replicative or stress-induced senescence is repeatedly used to mimic skin aging in vitro, thus presenting only a partial view of the complexity of aging.

Tspan8 Drives Melanoma Dermal Invasion by Promoting ProMMP-9 Activation and Basement Membrane Proteolysis in a Keratinocyte-Dependent Manner.

Melanoma is the most aggressive skin cancer with an extremely challenging therapy. The dermal-epidermal junction (DEJ) degradation and subsequent dermal invasion are the earliest steps of melanoma dissemination, but the mechanisms remain elusive. We previously identified Tspan8 as a key actor in melanoma invasiveness.

Keratinocyte stem cells are more resistant to UVA radiation than their direct progeny.

The epidermis undergoes constant renewal during its lifetime. This is possible due to a special population of keratinocyte stem cells (KSCs) located at the basal layer. These cells are surrounded by their direct progeny, keratinocyte progenitors or transient amplifying cells (TAs), which arise from cell division.