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With age, the dermal-epidermal junction (DEJ) becomes thinner and production of its protein components decreases; this may be associated with increased fragility and wrinkling of skin. Topical treatment with palmitoyl-Arg-Gly-Asp (PAL-RGD) improves facial wrinkles, skin elasticity and dermal density in humans. In the present study, the effect of PAL-RGD on expression of DEJ components, such as laminin and collagen, was assessed. Human HaCaT keratinocytes were treated with PAL-RGD. The protein expression levels of laminin-332, collagen IV and collagen XVII were examined by western blotting. Reverse transcription-quantitative PCR was used to analyze laminin subunit (LAM)A3, LAMB3, LAMC2, collagen type IV α 1 chain (COL4A1) and COL17A1 mRNA expression levels. Western blot analysis showed that the expression levels of proteins comprising the DEJ, including laminin α3, β3 and γ2 and collagen IV and XVII demonstrated a significant dose-dependent increase following PAL-RGD treatment. Furthermore, PAL-RGD treatment significantly enhanced LAMA3, LAMB3, LAMC2, COL4A1 and COL17A1 mRNA expression levels. PAL-RGD may enhance the DEJ by inducing the expression of laminin-332, collagen IV and collagen XVII. [ABSTRACT FROM AUTHOR]

Transdermal skin delivery is a method to transport various topical formulations to a deeper skin layer non-invasively. Permeability analysis of many delivering agents has been mostly conducted by a simple tape stripping method. However, it cannot reveal a detailed depth-dependent distribution profile of transdermally delivered agents in the skin. In this work, we achieved a cellular-level depth-defined visualization of fluorophore-labelled human epidermal growth factor (EGF) transdermally delivered to human skin by using encapsulation with common liposomes and newly fabricated multi-lamellar nanostructures using a custom-design two-photon microscopy system. It was able to generate 3D reconstructed images displaying the distribution of human EGF inside the human skin sample with high-resolution. Based on a depthwise fluorescence intensity profile showing the permeation of human EGF, a quantitative analysis was performed to assess the transdermal delivery efficacy achieved by each formulation, showing a significant improvement of the efficacy with the utilization of multi-lamellar nanostructure., Competing Interests: Jinhyo Ahn, Kibaek Choe, Pilhan Kim: CELLTRION Corporation (F) Kyeong Hu Kim, Joo Hyuck Lim, Seung Ki Lee, Yeon Sook Kim: CELLTRION Corporation (E,P,R).

The role of cyclohexane diester analogues in the formation of melanin has been recently reported. In the present study, we investigated the inhibitory effect of cyclohexanediol bis-ethylhexanoate (CHEH) on melanogenesis in B16 melanoma cells and on UV-B-induced pigmentation in human skin. CHEH significantly reduced the melanin content in a dose-dependent manner, without cytotoxic effects at the effective concentrations. Moreover, CHEH dose-dependently inhibited tyrosinase activity in B16 melanoma cells, as confirmed by Western blot analysis of the tyrosinase protein levels. However, tyrosinase transcript levels remained unchanged under the same experimental conditions. These results indicate that CHEH inhibited melanogenesis in B16 melanoma cells by regulating tyrosinase activity at the post-transcriptional level. On the other hand, in a cell-free system, CHEH did not inhibit tyrosinase activity. This indicated that CHEH suppressed the pigmentation of melanocytes by indirectly regulating tyrosinase activity. Finally, in a clinical trial, a cream containing 1.0% CHEH showed good whitening effect on UV-induced pigmented human skin without adverse effects. In conclusion, we suggest that CHEH may be an effective inhibitor of melanogenesis and useful effects in the treatment of hyperpigmented disorders.