E-cadherin mediates ultraviolet radiation- and calcium-induced melanin transfer in human skin cells.

Skin pigmentation is directed by epidermal melanin units, characterized by long-lived and dendritic epidermal melanocytes (MC) that interact with viable keratinocytes (KC) to contribute melanin to the epidermis. Previously, we reported that MC:KC contact is required for melanosome transfer that can be enhanced by filopodi, and by UVR/UVA irradiation, which can upregulate melanosome transfer via Myosin X-mediated control of MC filopodia. Both MC and KC express Ca -dependent E-cadherins.

TGF-beta-induced early gene-1 overexpression promotes oxidative stress protection and actin cytoskeleton rearrangement in human skin fibroblasts.

Background: Transforming growth factor beta inducible early gene-1 (TIEG-1), a member of the Krüppel-like factor, was identified as a primary response gene for TGF-β. The role of TIEG-1 in skin repair has been mainly addressed in vivo on TIEG-1 null mice model and the mechanism remains unexplored.

Methods: We investigated the modulation of TIEG-1 expression in normal human skin fibroblasts by either down-expressing or overexpressing the gene.

Differential expression of cathepsins K, S and V between young and aged Caucasian women skin epidermis.

Cutaneous aging translates drastic structural and functional alterations in the extracellular matrix (ECM). Multiple mechanisms are involved, including changes in protease levels. We investigated the age-related protein expression and activity of cysteine cathepsins and the expression of two endogenous protein inhibitors in young and aged Caucasian women skin epidermis.

Cleavage of nidogen-1 by cathepsin S impairs its binding to basement membrane partners.

Cathepsin S (catS), which is expressed in normal human keratinocytes and localized close to the dermal-epidermal junction (DEJ) degrades some of major basement membrane (BM) constituents. Among them, catS readily hydrolyzed in a time and dose dependent manner human nidogen-1 (nid-1) and nidogen-2, which are key proteins in the BM structure. CatS preferentially cleaved nid-1 at both acid and neutral pH.

Melanin transfer in human skin cells is mediated by filopodia--a model for homotypic and heterotypic lysosome-related organelle transfer.

Transfer of the melanocyte-specific and lysosome-related organelle, the melanosome, from melanocytes to keratinocytes is crucial for the protection of the skin against harmful ultraviolet radiation (UVR)--our main physiological cutaneous stressor. However, this commonplace event remains a most enigmatic process despite several early hypotheses. Recently, we and others have proposed a role for filopodia in melanin transfer, although conclusive experimental proof remained elusive.

Study of fibroblast gene expression in response to oxidative stress induced by hydrogen peroxide or UVA with skin aging.

The skin aging process, implying oxidative stress, is associated with specific gene expression. Ultraviolet A (UVA) and hydrogen peroxide (H(2)O(2)) both generate reactive oxygen species (ROS) making them relevant in the study of skin cell responses to oxidative stresses. To investigate transcript expression associated with chronological skin aging and its modulation by two oxidative stresses, cDNA micro-arrays, composed of a set of 81 expressed sequence tag (EST) clones, were used to probe the patterns of transcript expression in human fibroblasts of five young (< 21 years-old) and five older (> 50 years-old) healthy females at basal levels and 24 h after exposure to UVA (7 J/cm2) and H(2)O(2) (20 mM).

The silver locus product (Silv/gp100/Pmel17) as a new tool for the analysis of melanosome transfer in human melanocyte-keratinocyte co-culture.

Melanosomes are melanocyte-specific lysosome-related organelles that are transferred to keratinocytes of the epidermis and anagen hair bulb. Transferred melanin forms supra-nuclear caps that protect epidermal keratinocytes against UV irradiation. The mechanism(s) responsible for melanosome transfer into keratinocytes and their subsequent intra-keratinocyte distribution has long remained one of the most enigmatic of heterotypic cell interactions.

Modulation of gene expression as a new skin anti-aging strategy.

Background/objectives: [corrected] The signs of aging may originate from natural processes or from exposure to the sun, wind, or other environmental factors. To evaluate the anti-aging effects of potential agents researchers must first identify and be able to quantify epidermal markers that change with aging. This paper summarizes the results of studies conducted to evaluate the transcriptional effects of an Aframomum angustifolium seed extract and Malva Sylvestris extract, and the antiaging efficacy of a skin care product containing the Aframomum angustifolium seed extract.

In vivo skin antioxidant effect of a new combination based on a specific Vitis vinifera shoot extract and a biotechnological extract.

Background And Objectives: Ultraviolet (UV) light produces reactive oxygen species (ROS) in skin, which accelerate aging by damaging DNA, proteins, lipids, and other cellular constituents. The aims of this study were to 1) evaluate the antioxidant properties of a Vitis vinifera shoot extract on cultured normal human keratinocytes, 2) compare the in vivo antioxidant of this extract in combination with a biotechnological extract (Ronacare Hydroine), and 3) evaluate the efficacy on photoaging skin of a serum based on a combination (Vitis vinifera shoot extract in hydroglycolic solution, or Sarmentine, and Ronacare Hydroine) after a 4-week application, and to quantify the additional improvement given by applying a cream with the serum.

Methods/study Design: An in vitro study was conducted to evaluate the antioxidant properties of Vitis vinifera shoot extract added to cultured normal human keratinocytes.

The use of antisense strategy to modulate human melanogenesis.

Background And Objectives: Skin without significant dyschromia is an aesthetic goal of people worldwide. Current options for lightening skin could have significant drawbacks. The antisense strategy may be a viable alternative.

Transcriptional effect of an Aframomum angustifolium seed extract on human cutaneous cells using low-density DNA chips.

Background: Studying photoexposed and photoprotected skin biopsies from young and aged women, it has been found that a specific zone, composed of the basal layers of the epidermis, the dermal epidermal junction, and the superficial dermis, is major target of aging and reactive oxygen species. We showed that this zone is characterized by significant variations at a transcriptional and/or protein levels.

Aims: Using low-density DNA chip technology, we evaluated the effect of a natural mixture of Aframomum angustifolium seed extract containing labdane diterpenoids on these aging markers.

Skin ageing: clinical and histopathologic study of permanent and reducible wrinkles.

Wrinkles are modifications of the skin associated with cutaneous ageing and develop preferentially on sun-exposed skin. The aim of the study was to analyse the clinicopathological features of wrinkles, among the different types of skin relief modifications. Despite its importance in dermato-cosmetology and skin ageing, few studies have been specifically devoted to wrinkles.