ABSTRACT
The influence of all-trans retinoic acid (RA), either in its free or encapsulated form into wheat ceramides (CER), on the production of collagenase (MMP-1), and tissue inhibitor of metalloproteinase (TIMP-1) by human skin fibroblasts (HSF) at early and late stages of their proliferative life span (PLS) was examined. The level of MMP-1 was elevated and that of TIMP-1 decreased in late as compared to early passage cells. All-trans retinoic acid significantly decreased and increased the secretions of MMP-1 and TIMP-1 respectively, in a dose-dependent manner, from 10-7 m to 10-5 m. Entrapment of RA into CER vesicles potentiated its effect on MMP-1 and TIMP-1 secretions by HSF, independently of cell passages. The extent of variations obtained on MMP-1 and TIMP-1 levels, when HSF culture medium was supplemented with 10-5 m RA, could be obtained using a 100-fold lower concentration of RA encapsulated into CER vesicles. CER had no effect on TIMP-1 and MMP production by HSF in culture, and simultaneous addition of CER and RA did not potentiate the effects of RA alone, indicating that formation of RA-CER liposomes was responsible for the enhancing effects. The rate of internalization of RA into HSF was increased when used in its CER encapsulated form. Therefore, the use of retinoid within CER potentiates its beneficial influence on the MMP-1:TIMP-1 imbalance with fibroblastageing.
ABSTRACT
In vitro human skin fibroblasts aging was characterized by a continuous increase of collagenase mRNA levels. On the contrary, TIMP-1 mRNA level decreased only at late passages (> 65% of proliferative life span). Type I and III mRNA levels showed a high variability depending on cell strains studied. However, type I and III collagen expressions varied parallely. All-trans retinoic acid (RA) decreased collagenase expression and stimulated TIMP-1 expression. Under RA action, high variability in mRNAs levels encoding type I and III collagens was observed with HSF passages. However, RA tended to correct variations in collagens expressions observed along HSF life span.
Subject(s)
Collagen/drug effects , Collagenases/drug effects , Fibroblasts/drug effects , Glycoproteins/drug effects , Cell Division/drug effects , Cellular Senescence/drug effects , Cellular Senescence/genetics , Collagen/genetics , Collagenases/genetics , Fibroblasts/chemistry , Gene Expression Regulation/drug effects , Glycoproteins/genetics , Humans , Matrix Metalloproteinase Inhibitors , RNA, Messenger/analysis , Skin/cytology , Tissue Inhibitor of Metalloproteinases , Tretinoin/pharmacologyABSTRACT
Synopsis Ceramides, composed of sphingosine N-acyl linked to fatty acids have become widely used in cosmetology. They play several physiological roles in the regulation of skin barrier function. Human neutrophil elastase (HNE) can be inhibited by long-chain fatty acids and their derivatives; it was therefore postulated that plant ceramides could be inhibitors of HNE. Ceramides were extracted from wheat, isolated and characterized. The main fatty acids were 16:0, 18:1, 18:2 and the sphingoid moiety was phytosphingosine. Concentrations necessary to reach 50% inhibition of HNE were, respectively, 33 and 41 mug ml(-1) for non-glycosyl ceramides (CER) and glycosyl ceramides (gly-CER) when using a synthetic specific substrate. Similar extents of inhibition were obtained using a physiological substrate, insoluble elastin. Ex vivo studies showed that CER protected human skin elastic fibres against HNE degradation. Ceramides, being natural non-toxic substances, besides their role in cosmetics, could be of pharmacological interest in dermal inflammatory disorders.
