OBJECTIVETo evaluate the transfect results of recombinant adenovirus vector carrying tyrosinase gene (Ad-tyr) in vitro by magnetic resonance imaging (MRI) after the Ad-tyr was transfected into HepG2 cell.

METHODSThe Ad-tyr which carried the full-length cDNA of tyrosinase gene was transfected into HepG2 cell. The transfected cells were scan by MRI sequences of T1 weighted image (T1WI) , T2 weighted image (T2WI) , and short time inversion recovery (STIR) to observe the MRI signals of expressed melanin. Masson-Fontana staining was performed to search for melanin granules in transfected cells. Real-time PCR method was used to search for cDNA of tyrosinase gene.

RESULTSAd-tyr was transfected into HepG2 cells and synthesized a large amount of melanin inside. The synthesized melanin of 1 x 10(6) cells which had been transfected by Ad-tyr with the 50, 150, and 300 multiplicity of infection separately were all sufficient to be detected by MRI and showed high signals in MRI T1WI, T2WI, and STIR sequences. The signal intensities of MRI were positively correlated to the amounts of transfected Ad-tyr. The melanin granules were found in HepG2 cells in Masson-Fontana staining. The cDNA amount of tyrosinase gene in transfected HepG2 cells, which was detected by real-time PCR, was remarkably higher than that in nontransfected cells.

CONCLUSIONThe synthesized melanin of HepG2 cells, which controlled by expression of exogenous gene, can be detected by MRI, indicating that the adenovirus vector can efficiently carry the tyrosinase gene into HepG2 cells.

Adenoviridae ; genetics ; metabolism ; Gene Transfer Techniques ; Genetic Vectors ; genetics ; Hep G2 Cells ; Humans ; Magnetic Resonance Imaging ; methods ; Melanins ; analysis ; genetics ; Monophenol Monooxygenase ; biosynthesis ; genetics ; Transfection

Glycyrrhizin (GR), triterpenoid saponin composed of one glycyrrhetinic acid (GA) and two glucuronic acids, is a main constituent of the hydrophilic fraction of licorice (Glycyrrhiza glabra) extracts and is known to have a wide range of pharmacological actions. In this study, we investigated the mechanism of GR effect on melanogenesis in B16 murine melanoma cells. The cellular levels of tyrosinase mRNA, protein, enzyme activities and melanin contents were increased by GR in a dose dependent manner. Expression of tyrosinase-related protein-2 (TRP-2) mRNA was also increased by GR, however, no significant change was observed on TRP-1. No cytotoxicity was observed at the effective concentration range of GR. GA showed no effect on melanogenesis at the equivalent nontoxic concentrations, indicating that glycoside structure is important in the stimulatory effect of GR on melanogenesis. These results indicate that GR-induced stimulation of melanogenesis is likely to occur through the transcriptional activation.
Animal ; Blotting, Western ; Glycyrrhetinic Acid/pharmacology ; Glycyrrhizic Acid/*pharmacology ; Intramolecular Oxidoreductases/genetics/metabolism ; Melanins/*biosynthesis ; Melanoma, Experimental/enzymology/*metabolism ; Mice ; Monophenol Monooxygenase/genetics/metabolism ; Proteins/genetics/metabolism ; Reverse Transcriptase Polymerase Chain Reaction

Pigmentation may result from melanocyte proliferation, melanogenesis, migration or increases in dendricity. Recently, it has been reported that secreted phospholipase A2(sPLA2) known as a component of bee venom (BV), stimulates melanocyte dendricity and pigmentation. BV has been used clinically to control rheumatoid arthritis and to ameliorate pain via its anti-inflammatory and antinociceptive properties. Moreover, after treatment with BV, pigmentation around the injection sites was occasionally observed and the pigmentation lasted a few months. However, no study has been done about the effect of BV on melanocytes. Thus, in the present study, we examined the effect of BV on the proliferation, melanogenesis, dendricity and migration in normal human melanocytes and its signal transduction. BV increased the number of melanocytes dose and time dependently through PKA, ERK, and PI3K/Akt activation. The level of cAMP was also increased by BV treatment. Moreover, BV induced melanogenesis through increased tyrosinase expression. Furthermore, BV induced melanocyte dendricity and migration through PLA2activation. Overall, in this study, we demonstrated that BV may have an effect on the melanocyte proliferation, melanogenesis, dendricity and migration through complex signaling pathways in vitro, responsible for the pigmentation. Thus, our study suggests a possibility that BV may be developed as a therapeutic drug for inducing repigmentation in vitiligo skin.
Animals ; Base Sequence ; Bee Venoms/*pharmacology ; Cell Movement/drug effects ; Cell Proliferation/drug effects ; Cells, Cultured ; Cyclic AMP/metabolism ; DNA Primers/genetics ; Forskolin/pharmacology ; Gene Expression/drug effects ; Humans ; Melanins/biosynthesis ; Melanocytes/cytology/*drug effects/physiology ; Microphthalmia-Associated Transcription Factor/biosynthesis/genetics ; Monophenol Monooxygenase/biosynthesis/genetics ; Signal Transduction/drug effects

In this study, the essential oil from lotus flower extract, including petals and stamens, was assessed with regard to its effects on melanogenesis in human melanocytes. The lotus flower essential oil was shown to stimulate melanin synthesis and tyrosinase activity in a dose-dependent manner. The lotus flower essential oil induced the expression of tyrosinase, microphthalmia-associated transcription factor M (MITF-M), and tyrosinase-related proten-2 (TRP-2) proteins, but not tyrosinase mRNA. Moreover, it increased the phosphorylation of ERK and cAMP response element binding protein (CREB). In order to verify the effective components of the lotus flower oil, its lipid composition was assessed. It was found to be comprised of palmitic acid methyl ester (22.66%), linoleic acid methyl ester (11.16%), palmitoleic acid methyl ester (7.55%) and linolenic acid methyl ester (5.16%). Among these components, palmitic acid methyl ester clearly induced melanogenesis as the result of increased tyrosinase expression, thereby indicating that it may play a role in the regulation of melanin content. Thus, our results indicate that lotus flower oil may prove useful in the development of gray hair prevention agents or tanning reagents.
Blotting, Western ; Cell Proliferation ; Cyclic AMP/metabolism ; Cyclic AMP Response Element-Binding Protein/genetics/metabolism ; Flowers/*chemistry ; Gas Chromatography-Mass Spectrometry ; Humans ; Intramolecular Oxidoreductases/genetics/metabolism ; Lotus/*chemistry ; Melanins/*biosynthesis ; Melanocytes/*drug effects/metabolism ; Microphthalmia-Associated Transcription Factor/genetics/metabolism ; Monophenol Monooxygenase/genetics/metabolism ; Phosphorylation ; Plant Oils/*pharmacology ; RNA, Messenger/genetics/metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Skin/cytology/drug effects/metabolism

Xanthohumol (XH), the principal prenylflavonoid of the hop plant (Humulus lupulus L.), dose-dependently inhibited isobutylmethylxanthine (IBMX)-induced melanogenesis in B16 melanoma cells, with little cytotoxicity at the effective concentrations. Decreased melanin content was accompanied by reduced tyrosinase enzyme activity, protein and mRNA expression. The levels of tyrosinase-related protein 1 and 2 mRNAs were decreased by XH. XH also inhibited alpha-melanocyte stimulating hormone- or forskolin-induced increases in melanogenesis, suggesting an action on the cAMP-dependent melanogenic pathway. XH downregulated the protein and mRNA expression of microphthalmia-associated transcription factor (MITF), a master transcriptional regulator of key melanogenic enzymes. These results suggest that XH might act as a hypo-pigmenting agent through the downregulation of MITF in the cAMP-dependent melanogenic pathway.
1-Methyl-3-isobutylxanthine/pharmacology ; Animals ; Cell Line ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Down-Regulation ; Drug Antagonism ; Forskolin/pharmacology ; *Humulus ; Intramolecular Oxidoreductases/antagonists & inhibitors/biosynthesis ; Melanins/antagonists & inhibitors/*biosynthesis ; Melanocytes/*drug effects/*metabolism ; Melanoma, Experimental ; Membrane Glycoproteins/antagonists & inhibitors/biosynthesis ; Mice ; Microphthalmia-Associated Transcription Factor/antagonists & inhibitors ; Monophenol Monooxygenase/antagonists & inhibitors/biosynthesis/genetics ; Oxidoreductases/antagonists & inhibitors/biosynthesis ; Propiophenones/*pharmacology ; Signal Transduction/drug effects ; alpha-MSH/metabolism