Effect of regioisomers of hydroxystearic acids as peroxisomal proliferator-activated receptor agonists to boost the anti-ageing potential of retinoids.

INTRODUCTION: We report on the in vitro and ex vivo effects of chiral (R)-10-hydroxystearic acid (10-HSA) compared with other mono-hydroxystearic acid regioisomers and stearic acid (SA) together with its benefit when combined with retinol. METHODS: Following treatment with hydroxystearic acids peroxisomal proliferator-activated receptor alpha (PPARα) activity was determined in a luciferase reporter gene assay, collagen type I was assessed in primary human dermal fibroblasts by immunohistochemistry, modification of the intracellular fibroblast collagen proteome was studied by mass-spectrometry-based proteomics and collagen type III was assessed by immunohistochemistry on human ex vivo skin. RESULTS: 10-HSA was the most effective PPARα agonist (15.7× induction; p < 0.001), followed by 9-HSA (10.1× induction) and then 12-HSA (4.9× induction) with 17-HSA (1.7× induction) being similar to the effects of stearic acid (1.8× induction). Collagen type I levels were increased in primary human fibroblasts by 2.12× and 1.56× for 10-HSA and 9-HSA, respectively, in vitro with the10-HSA being significant (p < 0.05), whereas 12-HSA and SA had no statistical effect over the untreated control. 10-HSA and 12-HSA modified the intracellular fibroblast collagen proteome slightly with significant increases in collagen alpha-1 (VI) and alpha-3 (VI) proteins but only 10-HSA increased levels of collagen alpha-2 (V), alpha-1 (III), alpha-1 (I) and alpha-2 (I) (all p < 0.05) with the increases being significantly different between 10-HSA and 12-HSA for collagen alpha-1 (I), collagen-3 (VI) and collagen alpha-2 (I) (p < 0.01). Collagen type III in ex vivo skin was increased +47% (p < 0.05) by 0.05% (1.7 mM) retinol, +70% (p < 0.01) by 0.01% (0.33 mM) 10-HSA and the combination increased levels by +240% (p < 0.01 for either ingredient). CONCLUSION: Chiral (R)-10-HSA has been shown to be superior to 9, 12 and 17-HSA as a PPARα agonist. Moreover, 10-HSA stimulated collagen synthesis in monolayer fibroblast culture as assessed by proteomics and immunohistochemically. Furthermore, we also show the synergistic effects of 10-HSA with retinol on collagen III synthesis in skin explants. These results further highlight the efficacy of 10-HSA as a cosmetically acceptable PPARα agonist and anti-ageing ingredient.

INTRODUCTION: Nous rapportons les effets in vitro et ex vivo de l'acide chiral (R)-10-hydroxystéarique (10-HSA) par rapport à d'autres régioisomères d'acide mono-hydroxystéarique et à l'acide stéarique (SA) ainsi que ses avantages lorsqu'il est associé au rétinol. MÉTHODES: Après un traitement avec des acides hydroxystéariques, l'activité du récepteur alpha activé par les proliférateurs peroxysomaux (PPARα) a été déterminée dans un test du gène rapporteur de la luciférase, le collagène de type I a été évalué dans les fibroblastes dermiques humains primaires par immunohistochimie, la modification du protéome du collagène des fibroblastes intracellulaires a été étudiée par spectrométrie de masse. La protéomique et le collagène de type III ont été évalués par immunohistochimie sur la peau humaine ex vivo. RÉSULTATS: la 10-HSA était l'agoniste PPARα le plus efficace (induction 15,7X ; p<0,001), suivi de la 9-HSA (induction 10,1X) puis de la 12-HSA (induction 4,9X) avec la 17-HSA (induction 1,7X) étant similaire aux effets de l'acide stéarique (induction 1,8X). Les niveaux de collagène de type I ont été augmentés dans les fibroblastes humains primaires de 2,12X et 1,56X pour la 10-HSA et la 9-HSA respectivement in vitro, la 10-HSA étant significative (p<0,05) : alors que la 12-HSA et la SA n'ont eu aucun effet statistique sur le témoin non traité. La 10-HSA et la 12-HSA ont légèrement modifié le protéome du collagène des fibroblastes intracellulaires avec des augmentations significatives des protéines de collagène alpha-1 (VI) et alpha-3 (VI), mais seule la 10-HSA a augmenté les niveaux de collagène alpha-2 (V), alpha -1 (III), alpha-1 (I) et alpha-2 (I) (tous p<0,05) avec des augmentations significativement différentes entre 10-HSA et 12-HSA pour le collagène alpha-1 (I), le collagène- 3 (VI) et Collagène alpha-2 (I) (p<0,01). Le collagène de type III dans la peau ex vivo a augmenté de +47 % (p<0,05) de 0,05 % (1,7 mM) de rétinol, de +70 % (p<0,01) de 0,01 % (0,33 mM) de 10-HSA et la combinaison a augmenté les niveaux de +240 % (p<0,01 pour chaque ingrédient). CONCLUSION: La chiral (R)-10-HSA s'est avérée supérieure à 9, 12 et 17-HSA en tant qu'agoniste de PPARα. De plus, la 10-HSA a stimulé la synthèse de collagène dans la culture de fibroblastes monocouche telle qu'évaluée par protéomique et immunohistochimique. De plus, nous montrons également les effets synergiques de la 10-HSA avec le rétinol sur la synthèse du collagène III dans les explants de peau. Ces résultats soulignent en outre l'efficacité de la 10-HSA en tant qu'agoniste de PPARα et ingrédient anti-âge cosmétiquement acceptable.

Design, synthesis, and biological evaluation of novel selective peptide inhibitors of 11ß-hydroxysteroid dehydrogenase 1.

The enzyme 11ß-HSD1 plays a crucial role in the tissue-specific regulation of cortisol levels and it has been associated with various diseases. Inhibition of 11ß-HSD1 is an attractive intervention strategy and the discovery of novel selective 11ß-HSD1 inhibitors is of high relevance. In this study, we identified and evaluated a new series of selective peptide 11ß-HSD1 inhibitors with potential for skin care applications. This novel scaffold was designed with the aid of molecular modeling and two previously reported inhibitors. SAR optimization yielded highly active peptides (IC50 below 400 nM) that were inactive at 1 µM concentration against structurally related enzymes (11ß-HSD2, 17ß-HSD1 and 17ß-HSD2). The best performing peptides inhibited the conversion of cortisone into cortisol in primary human keratinocytes and the most active compound, 5d, was further shown to reverse cortisone-induced collagen damage in human ex-vivo tissue.

Novel 11ß-hydroxysteroid dehydrogenase 1 inhibitors reduce cortisol levels in keratinocytes and improve dermal collagen content in human ex vivo skin after exposure to cortisone and UV.

Activity and selectivity assessment of new bi-aryl amide 11ß-hydroxysteroid dehydrogenase 1 (11ß-HSD1) inhibitors, prepared in a modular manner via Suzuki cross-coupling, are described. Several compounds inhibiting 11ß-HSD1 at nanomolar concentrations were identified. Compounds 2b, 3e, 7b and 12e were shown to selectively inhibit 11ß-HSD1 over 11ß-HSD2, 17ß-HSD1 and 17ß-HSD2. These inhibitors also potently inhibited 11ß-HSD1 activity in intact HEK-293 cells expressing the recombinant enzyme and in intact primary human keratinocytes expressing endogenous 11ß-HSD1. Moreover, compounds 2b, 3e and 12e were tested for their activity in human skin biopsies. They were able to prevent, at least in part, both the cortisone- and the UV-mediated decreases in collagen content. Thus, inhibition of 11ß-HSD1 by these compounds can be further investigated to delay or prevent UV-mediated skin damage and skin aging.

Subversion of CtBP1-controlled macropinocytosis by human adenovirus serotype 3.

Endocytosis supports cell communication, growth, and pathogen infection. The species B human adenovirus serotype 3 (Ad3) is associated with epidemic conjunctivitis, and fatal respiratory and systemic disease. Here we show that Ad3 uses dynamin-independent endocytosis for rapid infectious entry into epithelial and haematopoietic cells. Unlike Ad5, which uses dynamin-dependent endocytosis, Ad3 endocytosis spatially and temporally coincided with enhanced fluid-phase uptake. It was sensitive to macropinocytosis inhibitors targeting F-actin, protein kinase C, the sodium-proton exchanger, and Rac1 but not Cdc42. Infectious Ad3 macropinocytosis required viral activation of p21-activated kinase 1 (PAK1) and the C-terminal binding protein 1 of E1A (CtBP1), recruited to macropinosomes. These macropinosomes also contained the Ad3 receptors CD46 and alpha v integrins. CtBP1 is a phosphorylation target of PAK1, and is bifunctionally involved in membrane traffic and transcriptional repression of cell cycle, cancer, and innate immunity pathways. Phosphorylation-defective S147A-CtBP1 blocked Ad3 but not Ad5 infection, providing a direct link between PAK1 and CtBP1. The data show that viruses induce macropinocytosis for infectious entry, a pathway used in antigen presentation and cell migration.