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Changes in the expression of cornified envelope (CE) components are a hallmark of numerous pathological skin conditions and aging, underlying the importance of this stratum corneum structure in the homeostasis of the epidermal barrier. We performed a detailed characterisation of LCE6A, a member of the Late Cornified Envelope protein family. Immunohistochemical and immunoblot experiments confirmed that LCE6A is expressed late during epidermal differentiation. Crosslinking assays of recombinant LCE6A performed either in situ on human skin sections or in vitro demonstrated that LCE6A is indeed a substrate of transglutaminases and crosslinked to CEs. LCE6A‐derived peptides containing a glutamine‐lysine sequence retained these properties of the full‐length protein and reinforced the mechanical resistance of CE submitted to sonication. We designed P26, a LCE6A‐derived biomimetic peptide that similarly reinforced CE in vitro, and evaluated its protective properties ex vivo, on human skin explants, and in two double blind and vehicle‐controlled clinical trials. P26 was able to protect the skin from barrier disruption, to limit the damage resulting from a defective barrier, and could improve the signs of aging such as loss of skin firmness and increased skin roughness. Hence, our detailed characterisation of LCE6A as a component of the CE enabled us to develop a LCE6A‐derived peptide, biologically active with a new and original mode of action that could be of great interest as a cosmetic ingredient and a pharmacologic agent. [ABSTRACT FROM AUTHOR]

Background: Sleep is one of the most important factors affecting overall health. During the night, the skin repairs damage caused by daily stresses. Melatonin plays a key role in this process. Toxins are removed, and cellular repair and growth hormone production are increased. Inter alia, this also decreases signs of intrinsic aging. Aims: The current study was intended to demonstrate the impact of a unique fraction of Melaleuca alternifolia (FMA) essential oil, on sleep and skin quality. Methods: The effect of FMA was investigated in vitro on skin cells, evaluating its antioxidant and anti‐inflammatory properties, and in an ex‐vivo study on human skin biopsies treated with FMA following stress induction. In addition, two clinical studies were performed on volunteers with life‐style‐related sleep complaints. In one study, sleep was measured using a noncontact monitoring device (SleepScore Labs, Max). A second study was conducted to assess skin anti‐aging effects. Results: In vitro application of FMA reduced IL‐8 and reactive oxygen species (ROS) generation in skin cells. This was confirmed ex vivo through a decrease in inflammatory markers and an increase in antioxidant enzymes after stress induction. Interestingly, FMA also upregulated melatonin‐associated genes. Real‐world sleep tracking revealed that FMA significantly improved sleep quality, relative to unscented control. In vivo applications also showed a reduction in signs of aging. Conclusion: These results provide initial data to suggest that this unique FMA delivers skin anti‐aging benefits via a two‐pronged mode of action, improving sleep quality, and reducing skin inflammatory and oxidative stress. [ABSTRACT FROM AUTHOR]

Human epidermal keratinocytes and dermal fibroblasts were co-cultured on polysulfone (PSU) membranes, previously coated or not with hyaluronan (HA), and compared to monocultured keratinocytes and fibroblasts. The purpose was to define the interplay between both cell types and how it is influenced. The co-cultures reduced types I and III collagen levels, indicating that keratinocytes exerted an inhibition on matrix synthesis by fibroblasts. On the other hand, the amounts of keratins 17 and 10 were increased, suggesting that fibroblasts stimulate the production of keratins by keratinocytes. In contrast with naked PSU membranes, HA coatings increased types I and III collagens mRNA (messenger ribonucleic acid) levels, suggesting that HA counteracts the inhibition produced by keratinocytes. Changes were also observed in the expression of metalloproteinases (MMPs) on HA-coated PSU membranes. The presence of keratinocytes increased MMP1 and MMP3 synthesis by fibroblasts whereas HA exerted an inhibitory effect on MMP2 expression that depended on the culture conditions. The TGF-β3 mRNA levels were very high in co-cultures on PSU, whereas TGF-β1 mRNA was rather low; this was amplified on HA-coated membranes. These data provide a deeper insight into the intercellular interactions between dermal fibroblasts and keratinocytes, and their modulation by the culture support of these cells. [ABSTRACT FROM AUTHOR]