Anti-Inflammatory Agents ; pharmacology ; Brain ; drug effects ; metabolism ; Humans ; NF-kappa B ; metabolism ; Neurons ; drug effects ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; alpha-MSH ; pharmacology

OBJECTIVETo investigate the expression of alpha-melanocyte-stimulating hormone (alpha-MSH) in human split-thickness skin autograft and the role of alpha-MSH in hyperpigmented process of the grafted skin.

METHODSImmunohistochemical technique was used to detect the expression and distribution of alpha-MSH in the split-thickness grafted skin and normal skin separately.

RESULTSThe expression of alpha-MSH in most of the split-thickness grafted skin was much stronger than the control skin. The positive ratio of alpha-MSH expression was 61.1% in the split-thickness grafted skin, 11.1% in the normal skin of the donor area and 16.7% in the normal skin around the recipient area. The expression of alpha-MSH in the split-thickness grafted skin was significant high, compared with the normal skins (P < 0.01). The expression of alpha-MSH in the normal skin of the donor area was no statistic remarkably differences compared to the normal skin around the recipient area.

CONCLUSIONThe results indicate that the expression of alpha-MSH may markedly increase in the split-thickness grafted skin and correlate with its pigmentation after the skin graft. Overexpression of alpha-MSH may play an important role in hyperpigmented process of the skin graft.

Adolescent ; Adult ; Child ; Female ; Humans ; Hyperpigmentation ; metabolism ; Male ; Melanins ; metabolism ; Skin ; metabolism ; Skin Transplantation ; Transplantation, Autologous ; Young Adult ; alpha-MSH ; metabolism

The pathogenesis of chronic cyclosporine A (CsA) nephrotoxicity has not been elucidated, but apoptosis is thought to play an important role in CsA induced tubular atrophy. Recently Fas-Fas ligand system mediated apoptosis has been frequently reported in many epithelial cells as well as in T lymphocytes. We investigated the ability of CsA to induce apoptosis in cultured human proximal tubular epithelial cells and also the effect of -MSH on them. Fas, Fas ligand, and an intracellular adaptor protein, Fas-associating protein with death domain (FADD) expression, and poly-ADP ribose polymerase (PARP) cleavage were also studied. CsA induced apoptosis in cultured tubular epithelial cells demonstrated by increased number of TUNEL positive cells and it was accompanied by a significant increase in Fas mRNA and Fas ligand protein expressions. FADD and the cleavage product of PARP also increased, indicating the activation of caspase. In -MSH co-treated cells, apoptosis markedly decreased with downregulation of Fas, Fas ligand and FADD expressions and also the cleavage product of PARP. In conclusion, these data suggest that tubular cell apoptosis mediated by Fas system may play a role in tubular atrophy in chronic CsA nephrotoxicity and pretreatment of -MSH may have a some inhibitory effect on CsA induced tubular cell apoptosis.
Antigens, CD95/genetics ; Apoptosis/*drug effects ; Carrier Proteins/biosynthesis ; Caspases/physiology ; Cells, Cultured ; Cyclosporine/*toxicity ; Human ; Immunosuppressive Agents/*toxicity ; Kidney Tubules, Proximal/cytology/*drug effects/metabolism ; Membrane Glycoproteins/biosynthesis ; NAD+ ADP-Ribosyltransferase/metabolism ; RNA, Messenger/analysis ; alpha-MSH/*pharmacology

Binding activity and biologic effect of a novel alpha-melanocyte-stimulating hormone analogue were tested on cells transiently expressing the human melanocortin-1 (MC1), MC3, MC4, and MC5 receptors. The human MC1 and MC5 receptor genes were cloned into the expression vector pcDNA3. 1/ myc-his(-) B. The vectors were transferred to HEK-293 cells by the calcium phosphate method. Stable receptor populations were generated using G418 selection (900 microg x mL(-1)) for subsequent bioassay analysis. K(i) values of the novel alpha-MSH analogue for MC1, MC3, MC4, and MC5 receptors were obtained in competition with [125I]-NDP-MSH for binding studies. The cyclic AMP level was tested by using [3H]-cyclic AMP kit. It is showed that K(i) values of the novel alpha-MSH analogue for MC1, MC3, MC4, and MC5 receptors were (0.159 +/- 0.040), (35.430 +/- 6.743), (19.293 +/- 2.780) and (2.230 +/- 0.670) nmol L(-1), respectively. Its EC50 values for MC1, MC3, MC4, and MC5 receptors were (0.45 +/- 0.07), (7.80 +/- 0.65), (2.55 +/- 0.23) and (0.33 +/- 0.09) nmol L(-1), respectively. In these tests, the novel alpha-MSH analogue is a MC1R and MC5R selective agonist.
Amino Acid Sequence ; Binding, Competitive ; Cell Line ; Cell Line, Tumor ; Cyclic AMP ; metabolism ; Genetic Vectors ; Humans ; Iodine Radioisotopes ; Kinetics ; Molecular Sequence Data ; Plasmids ; genetics ; Radioligand Assay ; Receptor, Melanocortin, Type 1 ; agonists ; genetics ; metabolism ; Receptors, Corticotropin ; agonists ; genetics ; metabolism ; Receptors, Melanocortin ; agonists ; genetics ; metabolism ; Transfection ; Tritium ; alpha-MSH ; analogs & derivatives ; chemistry ; metabolism ; pharmacology

OBJECTIVE: To explore the effects of taurolithocholic acid (tLCA) and chenodeoxycholic acid (CDCA) on the expression of aorexigenic neuropeptide in mouse hypothalamus GT1-7 cells. METHODS: Mouse hypothalamic GT1-7 cells were treated with culture medium containing 10% FBS (control group, =3) or with 10 nmol/L, 100 nmol/L, 1 μmol/L and 10 μmol/L tLCA (tLCA group, =3) or CDCA (CDCA group, =3) for 12, 24 or 48 h. Real-time PCR was performed to determine the expression levels of proopiomelanocortin (POMC) mRNA in the cells, and the production levels of α-melanocyte-stimulating hormone (α-MSH) were assessed using an ELISA kit. Signal transduction and activator of transcription 3 phosphorylation (p-STAT3), threonine kinase phosphorylation (p-AKT), suppressor of cytokine signaling 3 (SOCS3), G protein-coupled bile acid receptor-1 (TGR5) and farnesoid X receptor (FXR) protein were detected by Western blotting. RESULTS: Western blotting results showed that mouse hypothalamic GT1-7 cells expressed two bile acid receptors, TGR5 and FXR, whose expressions were regulated by bile acids. Real-time PCR showed that the expression of POMC mRNA was significantly increased in the cells after treatment with 10 μmol/L tLCA or CDCA for 24 h. POMC-derived anorexigenic peptide α-MSH increased significantly in GT1-7 cells after treatment with 10 μmol/L tLCA or CDCA for 24 h. Treatment of the cells with tLCA or CDCA significantly increased the expressions of intracellular signaling proteins including p-STAT3, p-AKT and SOCS3. CONCLUSIONS Mouse hypothalamic GT1-7 cells express bile acid receptors TGR5 and FXR. Bile acids tLCA or CDCA can promote the expression of POMC mRNA and increase the production of the anorexigenic peptide α-MSH. The intracellular signaling proteins p-AKT, p-STAT3 and SOCS3 are likely involved in bile acid-induced anorexigenic peptide production.
Animals ; Cell Line ; Chenodeoxycholic Acid ; pharmacology ; Gene Expression Regulation ; drug effects ; Hypothalamus ; cytology ; Mice ; Neuropeptides ; genetics ; metabolism ; Pro-Opiomelanocortin ; genetics ; RNA, Messenger ; genetics ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Suppressor of Cytokine Signaling 3 Protein ; metabolism ; Taurolithocholic Acid ; pharmacology ; alpha-MSH ; genetics

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