ABSTRACT
BACKGROUND: Cutaneous wound healing is a complex process involving various regulatory factors at the molecular level. Aloe vera is widely used for cell rejuvenation, wound healing, and skin moisturizing. HYPOTHESIS/PURPOSE: This study aimed to investigate the effects of aloesin from Aloe vera on cutaneous wound healing and mechanisms involved therein. STUDY DESIGN: This study consisted of both in vitro and in vivo experiments involving skin cell lines and mouse model to demonstrate the wound healing effects of aloesin by taking into account several parameters ranging from cultured cell migration to wound healing in mice. METHODS: The activities of Smad signaling molecules (Smad2 and Smad3), MAPKs (ERK and JNK), and migration-related proteins (Cdc42, Rac1, and α-Pak) were assessed after aloesin treatment in cultured cells (1, 5 and 10µM) and mouse skin (0.1% and 0.5%). We also monitored macrophage recruitment, secretion of cytokines and growth factors, tissue development, and angiogenesis after aloesin treatment using IHC analysis and ELISAs. RESULTS: Aloesin increased cell migration via phosphorylation of Cdc42 and Rac1. Aloesin positively regulated the release of cytokines and growth factors (IL-1ß, IL-6, TGF-ß1 and TNF-α) from macrophages (RAW264.7) and enhanced angiogenesis in endothelial cells (HUVECs). Aloesin treatment accelerated wound closure rates in hairless mice by inducing angiogenesis, collagen deposition and granulation tissue formation. More importantly, aloesin treatment resulted in the activation of Smad and MAPK signaling proteins that are key players in cell migration, angiogenesis and tissue development. CONCLUSION: Aloesin ameliorates each phase of the wound healing process including inflammation, proliferation and remodeling through MAPK/Rho and Smad signaling pathways. These findings indicate that aloesin has the therapeutic potential for treating cutaneous wounds.
Subject(s)
Chromones/pharmacology , Glucosides/pharmacology , Skin/drug effects , Smad Proteins/metabolism , Wound Healing/drug effects , Aloe/chemistry , Animals , Cell Movement/drug effects , Cells, Cultured , Collagen/metabolism , Cytokines/metabolism , Human Umbilical Vein Endothelial Cells/drug effects , MAP Kinase Signaling System/drug effects , Macrophages/drug effects , Macrophages/metabolism , Mice, Hairless , Phosphorylation/drug effects , Signal Transduction/drug effects , Skin/metabolism , Skin/pathology , Tumor Necrosis Factor-alpha/metabolism , rac1 GTP-Binding Protein/metabolismABSTRACT
Gomisin N, one of the lignan compounds found in Schisandra chinensis has been shown to possess anti-oxidative, anti-tumorigenic, and anti-inflammatory activities in various studies. Here we report, for the first time, the anti-melenogenic efficacy of Gomisin N in mammalian cells as well as in zebrafish embryos. Gomisin N significantly reduced the melanin content without cellular toxicity. Although it was not capable of modulating the catalytic activity of mushroom tyrosinase in vitro, Gomisin N downregulated the expression levels of key proteins that function in melanogenesis. Gomisin N downregulated melanocortin 1 receptor (MC1R), adenylyl cyclase 2, microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2). In addition, Gomisin N-treated Melan-A cells exhibited increased p-Akt and p-ERK levels, which implies that the activation of the PI3K/Akt and MAPK/ERK pathways may function to inhibit melanogenesis. We also validated that Gomisin N reduced melanin production by repressing the expression of MITF, tyrosinase, TRP-1, and TRP-2 in mouse and human cells as well as in developing zebrafish embryos. Collectively, we conclude that Gomisin N inhibits melanin synthesis by repressing the expression of MITF and melanogenic enzymes, probably through modulating the PI3K/Akt and MAPK/ERK pathways.
Subject(s)
Lignans/pharmacology , Melanins/biosynthesis , Melanocytes/metabolism , Mitogen-Activated Protein Kinases/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Polycyclic Compounds/pharmacology , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/drug effects , Animals , Cell Line, Tumor , Cell Survival/drug effects , Cyclooctanes/pharmacology , Enzyme Activation/drug effects , Humans , Melanocytes/drug effects , Mice , Monophenol Monooxygenase/metabolism , Phosphorylation , Receptor, Melanocortin, Type 1/metabolism , ZebrafishABSTRACT
We already reported that genetically engineered resveratrol-enriched rice (RR) showed to down-regulate skin melanogenesis. To be developed to increase the bioactivity of RR using calli from plants, RR was adopted for mass production using plant tissue culture technologies. In addition, high-pressure homogenization (HPH) was used to increase the biocompatibility and penetration of the calli from RR into the skin. We aimed to develop anti-melanogenic agents incorporating calli of RR (cRR) and nanoparticles by high-pressure homogenization, examining the synergistic effects on the inhibition of UVB-induced hyperpigmentation. Depigmentation was observed following topical application of micro-cRR, nano-calli of normal rice (cNR), and nano-cRR to ultraviolet B (UVB)-stimulated hyperpigmented guinea pig dorsal skin. Colorimetric analysis, tyrosinase immunostaining, and Fontana-Masson staining for UVB-promoted melanin were performed. Nano-cRR inhibited changes in the melanin color index caused by UVB-promoted hyperpigmentation, and demonstrated stronger anti-melanogenic potential than micro-cRR. In epidermal skin, nano-cRR repressed UVB-promoted melanin granules, thereby suppressing hyperpigmentation. The UVB-enhanced, highly expressed tyrosinase in the basal layer of the epidermis was inhibited by nano-cRR more prominently than by micro-cRR and nano-cNR. The anti-melanogenic potency of nano-cRR also depended on pH and particle size. Nano-cRR shows promising potential to regulate skin pigmentation following UVB exposure.
