30 research outputs found
Modelling the human epidermis in vitro: tools for basic and applied research
Culture models of tissues and organs are valuable tools developed by basic research that help investigation of the body functions. Modelling is aimed at simplifying experimental procedures in order to better understand biological phenomena, and consequently, when sufficiently characterized, culture models can also be utilized with high potential in applied research. In skin biology and pathology, the development of cultures of keratinocytes as monolayers has allowed the elucidation of most functional and structural characteristics of the cell type. Beside the multiple great successes that have been obtained with this type of culture, this review draws attention on several neglected characteristics of monolayer cultures. The more sophisticated models created in order to reconstruct the fully differentiated epidermis have followed the monolayers. The epidermal reconstruction produces all typical layers found in vivo and thus makes the model much less simple, but only this kind of model allows the study of full differentiation in keratinocyte and production of the cornified barrier. In addition to its interest in basic research, the reconstructed epidermis is currently gaining a lot of interest for applied research, particularly as an alternative to laboratory animals in the chemical and cosmetic industry. Today several commercial providers propose reconstructed skin or epidermis, but in vitro assays on these materials are still under development. In order to be beneficial at long term, the validation of assays must be performed on a material whose availability will not be interrupted. We warn here providers and customers that the longevity of in vitro assays will be guaranteed only if these assays are done with well-described models, prepared according to published procedures, and must consider having a minimum of two independent simultaneous producers of similar material
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911 Theophylline exerts complex anti-aging and anti-cytotoxicity effects in human skin ex vivo
Theophylline exerts complex antiâageing and antiâcytotoxicity effects in human skin ex vivo
Objective
Theophylline is a phosphodiesterase inhibitor that is being used clinically for asthma therapy. In addition, it is recognized as a cosmetic agent with possible antiâageing and antiâoxidative properties. Nevertheless, how it affects human skin is still poorly examined.
Methods
Theophylline (10 or 100 ”M) was administered to the culture medium of fullâthickness human skin ex vivo for 24 or 72 h.
Results
Theophylline stimulated protein expression of the antiâoxidant metallothioneinâ1 and mRNA levels of collagen I and III. Assessment of fibrillinâ1 immunohistology revealed enhanced structural stability of dermal microfibrils. Theophylline also exerted extracellular matrixâprotective effects by decreasing MMPâ2 and MMPâ9 mRNA levels, partially antagonizing the effects of menadione, the potent, toxic ROS donor. In addition, it decreased menadioneâstimulated epidermal keratinocytes apoptosis. Interestingly, theophylline also increased the level of intracutaneously produced melatonin, that is the most potent ROSâprotective and DNA damage repair neuromediator, and tendentially increased protein expression of MT1, the melatonin receptor. Theophylline also increased the expression of keratin 15, the stem cell marker, in the epidermal basal layer but did not change mitochondrial activity or epidermal pigmentation.
Conclusion
This ex vivo pilot study in human skin shows that theophylline possesses several interesting complex skinâprotective properties. It encourages further examination of theophylline as a topical candidate for antiâageing treatment.
Résumé
Objectif
la thĂ©ophylline est un inhibiteur de la phosphodiestĂ©rase actuellement utilisĂ©e en clinique pour le traitement de lâasthme. En outre, elle est reconnue comme Ă©tant un agent cosmĂ©tique ayant des propriĂ©tĂ©s potentiellement antiâĂąge et antioxydantes. Cependant, la maniĂšre dont elle affecte la peau chez lâhomme est encore trĂšs peu Ă©tudiĂ©e.
MĂ©thodes
de la thĂ©ophylline (10 ou 100 ÎŒM) a Ă©tĂ© ajoutĂ©e dans le milieu de culture dâun Ă©chantillon de peau humaine dâĂ©paisseur totale ex vivo pendant 24 ou 72 h.
RĂ©sultats
la thĂ©ophylline a stimulĂ© lâexpression de la mĂ©tallothionĂ©ineâ1, une protĂ©ine antioxydante, et les taux dâARNm du collagĂšne I et III. LâĂ©valuation immunohistologique de la fibrillineâ1 a rĂ©vĂ©lĂ© une meilleure stabilitĂ© structurale des microfibrilles du derme. La thĂ©ophylline a Ă©galement exercĂ© des effets protecteurs sur la matrice extracellulaire en diminuant les taux dâARNm des mĂ©talloprotĂ©inases matricielles MMPâ2 et MMPâ9, neutralisant en partie les effets de la mĂ©nadione, puissant donneur dâespĂšces rĂ©actives de l'oxygĂšne (ROS) toxiques. En outre, elle a diminuĂ© lâapoptose des kĂ©ratinocytes Ă©pidermiques stimulĂ©s par la mĂ©nadione. Fait intĂ©ressant, la thĂ©ophylline a Ă©galement augmentĂ© le taux de mĂ©latonine produite de maniĂšre intraâcutanĂ©e, la mĂ©latonine Ă©tant le plus puissant neuromĂ©diateur protecteur contre les ROS et rĂ©parateur des lĂ©sions de lâADN. Elle a augmentĂ© de façon tendancielle lâexpression de la protĂ©ine MT1, rĂ©cepteur de la mĂ©latonine. La thĂ©ophylline a Ă©galement augmentĂ© lâexpression de la kĂ©ratine 15, marqueur de cellules souches, dans la couche basale Ă©pidermique, mais nâa pas modifiĂ© lâactivitĂ© mitochondriale ou la pigmentation Ă©pidermique.
Conclusion
cette Ă©tude pilote ex vivo rĂ©alisĂ©e sur de la peau humaine montre que la thĂ©ophylline a plusieurs propriĂ©tĂ©s protectrices de la peau complexes et intĂ©ressantes. Ces rĂ©sultats encouragent Ă poursuivre lâĂ©tude de la thĂ©ophylline en tant que candidat Ă un traitement local antiâĂąge.
Theophylline is a phosphodiesterase inhibitor that is being used clinically for asthma therapy and recognized as a cosmetic agent. This pilot study in organâcultured middleâaged skin shows that theophylline possesses several interesting and surprisingly complex skinâprotective, antiâageing and antiâoxidative properties. This encourages further systematic examination of theophylline as a topical candidate for antiâageing
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Lysosomal membrane permeabilization in cell death
18 påginas, 3 figuras, 2 tablas -- PAGS nros. 6434-6451Mitochondrial outer membrane permeabilization (MOMP) constitutes one of the major checkpoint(s) of apoptotic and necrotic cell death. Recently, the permeabilization of yet another organelle, the lysosome, has been shown to initiate a cell death pathway, in specific circumstances. Lysosomal membrane permeabilization (LMP) causes the release of cathepsins and other hydrolases from the lysosomal lumen to the cytosol. LMP is induced by a plethora of distinct stimuli including reactive oxygen species, lysosomotropic compounds with detergent activity, as well as some endogenous cell death effectors such as Bax. LMP is a potentially lethal event because the ectopic presence of lysosomal proteases in the cytosol causes digestion of vital proteins and the activation of additional hydrolases including caspases. This latter process is usually mediated indirectly, through a cascade in which LMP causes the proteolytic activation of Bid (which is cleaved by the two lysosomal cathepsins B and D), which then induces MOMP, resulting in cytochrome c release and apoptosome-dependent caspase activation. However, massive LMP often results in cell death without caspase activation; this cell death may adopt a subapoptotic or necrotic appearance. The regulation of LMP is perturbed in cancer cells, suggesting that specific strategies for LMP induction might lead to novel therapeutic avenuesResearch in our labs is supported by grants from Ministry of Science (BFU-2006-00508) and from Fundación La Caixa (BM06-125-1) to PB and Ligue Nationale contre le Cancer (Equipe labellisée), European Commission (Active p53, Apo-Sys, RIGHT, TransDeath, ChemoRes, DeathTrain), Agence Nationale pour la Recherche, Institut National contre le Cancer, CancéropÎle Ile-de-France and Fondation pour la Recherche Médicale to GKPeer reviewe