Antiaging effect of inotodiol on oxidative stress in human dermal fibroblasts.

Oxidative damage is one of the major causes of human skin aging. Inotodiol is a lanostane triterpenoid that demonstrates antiviral, anticancer, and anti-inflammatory activities. Previous studies have reported that inotodiol also has antiallergic effects. However, whether inotodiol inhibits oxidative stress-induced human skin aging is not known. Stimulation of human dermal fibroblast cells with hydrogen peroxide is related to skin aging. Inotodiol inhibited the expression of mitogen-activated protein kinase (MAPK) and NADPH Oxidase 5 (NOX5). Moreover, inotodiol effectively decreased nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), as well as nitric oxide (NO), reactive oxygen species (ROS), cyclooxygenase-2 (COX-2), and cytokines such as IL-1ß, IL-6, and TNF-α. Based on our results, inotodiol protects human dermal fibroblast by preventing MAPK-NOX5 and NF-κB activation and attenuates the expression of aging genes. Inotodiol may therefore be considered a potential candidate for developing natural antiaging products, because it protects the human skin from oxidative stress-induced skin aging by inhibiting the MAPK-NOX5 and NF-κB signaling pathways.

Variation of Triterpenic Acids in 12 Wild Syzygium formosum and Anti-Inflammation Activity on Human Keratinocyte HaCaT.

Syzygium formosum (Wall.) Masam leaf is known as a Vietnamese traditional herbal medicine used to treat atopic dermatitis and stomach ulcers. Recently, its potent anti-allergic effects were reported with possible active compounds analysis. Here, we collected S. formosum leaves from 12 wild trees and compared compositions of triterpenic acids (TA) with Centella asiatica. Anti-inflammatory activities of S. formosum leaf extract (SFLE) was compared with C. asiatica extract (CAE) using human keratinocyte, HaCaT. In this study, up to seven TAs were identified in SFLE, while only madecassic and asiatic acids were detected in the CAE. Total TA content varied among SFLE, but asiatic, corosolic, and betulinic acids were the major components. Surprisingly, wild tree sample 12 (S12) contained total TA of 27.2 mg/g dry-leaves that was 5-fold greater than that in the C. asiatica sample, and S4 had the highest content of asiatic acid (12.6 mg/g dry-leaves) that accounted for 50% of the total TA. S4 and S12 showed more than 3-fold higher anti-oxidative power than the CAE. In the UVB irradiation model, S4 and S12 (5 µg/mL) strongly repressed mRNA levels of pro-inflammatory cytokines (IL-1ß, IL-6, and IL-8) and COX-2, while the CAE at the same condition showed moderate or weak repression. The difference in anti-inflammation effects between the SFLE and the CAE was also confirmed by protein quantifications. Taken together, SFLE has great potentials as a new cosmeceutical ingredient with a higher amount of skin-active phytochemicals.

Traditional herbal prescription LASAP-C inhibits melanin synthesis in B16F10 melanoma cells and zebrafish.

BACKGROUND: In this study, the anti-melanogenesis efficacy of clinically used herbal prescription LASAP-C, which consists of four herbal medicines-Rehmanniae Radix Crudus, Lycii Fructus, Scutellariae Radix, and Angelicae Dahuricae Radix, was investigated. METHODS: The chemical profile of LASAP-C was established by conducting ultra-performance liquid chromatography-electrospray ionization-mass spectrometry. Anti-melanogenic efficacy was evaluated by tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 expression in B16F10 melanoma cells. In vivo evaluation was performed by using zebrafish model. RESULTS: Molecular evidences suggested that melanin synthesis was inhibited via the down-regulation of tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 expression in B16F10 melanoma cells treated with LASAP-C. The anti-melanogenesis efficacy was also confirmed in vivo by using the zebrafish model. CONCLUSION: The results of this study provide strong evidences that LASAP-C can be used as an active component in cosmeceutical products for reducing excess pigmentation in the human skin.

Effect of adenosine on melanogenesis in b16 cells and zebrafish.

BACKGROUND: Adenosine is a nucleoside, in which an adenine molecule is attached to a ribofuranose sugar moiety. It can be released into the microenvironment by metabolically active cells, and then fulfills a multitude of functions in regulation of cell proliferation, by activating four subtypes of G protein-coupled adenosine receptors. OBJECTIVE: In this study, we investigated the effect of adenosine on melanogenesis, using B16 melanoma cells. METHODS: The toxic effects of adenosine on B16 melanoma cells were assessed. To understand the mechanism of the effect of adenosine on melanogenesis in B16 cells, melanin content and tyrosinase activity were measured. Tyrosinase, tyrosinase-related protein-1, and dopachrome tautomerase were monitored by Western blotting. Finally, adenosine was applied to zebrafish embryos, and its in vivo effect on pigmentation investigated. RESULTS: At a low concentration, adenosine increased melanin content and tyrosinase activity, while a high dose of adenosine resulted in inhibition of tyrosinase activity. Western blotting showed that adenosine increased tyrosinase protein levels slightly, while high-dose adenosine decreased the expression of tyrosinase. In zebrafish tests, adenosine slightly inhibited body pigmentation. CONCLUSION: In this study, we investigated the effect of adenosine on melanogenesis, using the well-established B16 melanoma cell and zebrafish models. The results suggest that adenosine may inhibit pigmentation, through negative regulation of tyrosinase.

Nrf2 negatively regulates melanogenesis by modulating PI3K/Akt signaling.

Nrf2 plays a role in protection of cells against oxidative stress and xenobiotic damage by regulating cytoprotective genes. In this study, we investigated the effect of Nrf2 on melanogenesis in normal human melanocytes (NHMCs). When NHMCs were transduced with a recombinant adenovirus expressing Nrf2, melanin synthesis was significantly decreased. Consistent with this result, overexpression of Nrf2 decreased the expression of tyrosinase and tyrosinase-related protein 1. The inhibitory effect of Nrf2 was reversed by overexpression of Keap1, an intracellular regulator of Nrf2. Interestingly, Nrf2 overexpression resulted in marked activation of PI3K/Akt signaling. Conversely, inhibition of PI3K activity by treatment with wortmannin reversed the depigmentary effects of Nrf2. Taken together, these results strongly suggest that Nrf2 negatively regulates melanogenesis by modulating the PI3K/Akt signaling pathway.

Inhibitory Effect of Arctigenin from Fructus Arctii Extract on Melanin Synthesis via Repression of Tyrosinase Expression.

To identify the active compound arctigenin in Fructus Arctii (dried seed of medicinal plant Arctium lappa) and to elucidate the inhibitory mechanism in melanogenesis, we analyzed melanin content and tyrosinase activity on B16BL6 murine melanoma and melan-A cell cultures. Water extracts of Fructus Arctii were shown to inhibit tyrosinase activity in vitro and melanin content in α -melanocyte stimulating hormone-stimulated cells to similar levels as the well-known kojic acid and arbutin, respectively. The active compound arctigenin of Fructus Arctii displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin content and tyrosinase activity in a dose-dependent manner. Melanogenic inhibitory activity was also identified in vivo with zebrafish embryo. To determine the mechanism of inhibition, the effects of arctigenin on tyrosinase gene expression and tyrosinase promoter activity were examined. Also in addition, in the signaling cascade, arctigenin dose dependently decreased the cAMP level and promoted the phosphorylation of extracellular signal-regulated kinase. This result suggests that arctigenin downregulates cAMP and the tyrosinase enzyme through its gene promoter and subsequently upregulates extracellular signal-regulated kinase activity by increasing phosphorylation in the melanogenesis signaling pathway, which leads to a lower melanin content.

MKK6 increases the melanocyte dendricity through the regulation of Rho family GTPases.

BACKGROUND: Melanocyte dendrites serve as the principal conduit for melanosome transfer. The dendrite formation requires actin polymerization mediated by Rho family GTPases including RhoA, Rac1 and Cdc42. OBJECTIVE: The aim of this study is to investigate and explore the involvement of p38 MAPK in melanocyte dendrite formation. METHODS: We transduced melanoma cells with adenovirus harboring the expression cassette for constitutive active form of MKK6, an upstream MAPKK for p38 MAPK. RESULTS: We investigated the effect of melanogenic inducers on melanocyte dendricity, using SK-mel-24 melanoma cells because that this cell line is refractory to several melanogenic inducers in terms of melanogenesis. TPA-induced the phosphorylation of p38 MAPK and the elongation of dendrite length, suggesting that MKK6 may be involved in this process. Overexpression of the constitutive active form of MKK6 resulted in significant elongation of dendrites in the melanoma cell line SK-mel-24. Moreover, overexpression of MKK6 ultimately led to the upregulation of Cdc42 and Rac1, suggesting that MKK6 acts as a crucial upstream signaling molecule for Rho family GTPases. When overexpressed in normal human epidermal melanocytes, MKK6 led also the increase of dendrite length. CONCLUSION: These results suggest that MKK6 is an authentic regulator for melanocytes dendricity, through the modulation of Rho family GTPases.

Beta-catenin regulates melanocyte dendricity through the modulation of PKCzeta and PKCdelta.

The Wnt/beta-catenin signaling pathway is involved in the melanocyte differentiation and melanoma development. However, the effect of beta-catenin for dendrite formation has not been clearly elucidated yet in normal human epidermal melanocytes (NHEM). To investigate the effect of beta-catenin, we transduced NHEM with recombinant adenovirus expressing beta-catenin. Forced expression of beta-catenin led to the dramatic morphological changes of NHEM, including the reduction of dendrite length and enlargement of cell body. Concomitantly with, the protein levels for dendrite formation-related molecules, such as Rac1 and Cdc42, were markedly decreased. In addition, phosphorylation of p38 MAPK was significantly reduced by beta-catenin, potentiating its inhibitory role for dendrite formation. Interestingly, overexpression of beta-catenin led to the increase of protein kinase C zeta (PKCzeta) level, while protein kinase C delta (PKCdelta) was decreased by beta-catenin, suggesting that those PKCs were beta-catenin-downstream modulators in NHMC. When PKCzeta was overexpressed, dendrites were shortened, with the reduced protein levels for Rac1 and Cdc42. In contrast, PKCdelta overexpression led to the elongation of dendrites, with the increased levels for Rac1 and Cdc42. These results suggest that beta-catenin play an inhibitory role for dendrite formation through the modulation of PKCzeta and PKCdelta.

Angiolymphoid hyperplasia with eosinophilia that was possibly induced by vaccination in a child.

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a rare benign vasoproliferative disease of an unknown cause involving the skin or subcutaneous tissue of the head and neck, and particularly around the ear. It predominantly affects Caucasian adults during the third and fourth decades and it very rarely occurs in children. We experienced a case of ALHE in a 2-year-old Korean boy who had a firm, pruritic, skin-colored, subcutaneous nodule on his right upper arm. The histopathological findings were compatible with ALHE and they showed prominent vascular changes with epitheloid or histiocytoid endothelial cells surrounded by inflammatory cells, including a large proportion of eosinophils. This unusual distribution of the lesion and the young age of the patient may be associated with vaccination.