• BMB Reports
• /
• v.46 no.7
• /
• pp.364-369
• /
• 2013

Endothelin-1 (ET-1) plays an indispensable role in epidermal pigmentation in hyperpigmentary disorders due to a central role in melanogenesis. Nevertheless, precise mechanism involved in ET-1-induced hyperpigmentation is still undefined. Glycoprotein (transmembrane) non-metastatic melanoma protein b (GPNMB) is a key element in melanosome formation. Therefore, we speculated that GPNMB was correlated with ET-1-induced pigmentation. After culturing with ET-1, melanin synthesis was significantly up-regulated, accompanying with increased expression of GPNMB and microphthalmia-associated transcription factor (MITF). Total number of melanosomes and melanin synthesis were sharply reduced via GPNMB-siRNA transfection, indicating ET-1-induced pigmentation by GPNMB-dependent manner. Furthermore, MITF-siRNA transfection strikingly inhibited GPNMB expression and the melanogenesis, and this suppression failed to be alleviated by ET-1 stimulation. All of these results demonstrated that ET-1 can trigger melanogenesis via the MITF-regulated GPNMB pathway. Taken together, these findings will provide a new explanation of how ET-1 induces hyperpigmentation, and possibly supply a new strategy for cosmetic studies.

• IMMUNE NETWORK
• /
• v.8 no.2
• /
• pp.53-58
• /
• 2008

Background: Molecular mechanisms of natural killer (NK) cell development from hematopoietic stem cells (HSCs) have not been clearly elucidated, although the roles of some genes in NK cell development have been reported previously. Thus, searching for molecules and genes related NK cell developmental stage is important to understand the molecular events of NK cell development. Methods: From our previous SAGE data-base, Gpnmb (Glycoprotein non-metastatic melanoma protein B) was selected for further analysis. We confirmed the level of mRNA and protein of Gpnmb through RT-PCR, quantitative PCR, and FACS analysis. Then we performed cell-based ELISA and FACS analysis, to know whether there are some molecules which can bind to Gpnmb. Using neutralizing antibody, we blocked the interaction between NK cells and OP9 cells, and checked IFN-${\gamma}$ production by ELISA kit. Results: Gpnmb expression was elevated during in vitro developmental stage and bound to OP9 cells, but not to NK precursor cells. In addition, we confirmed that the levels of Gpnmb were increased at NK precursor stage in vivo. We confirmed syndecan4 as a candidate of Gpnmb's binding molecule. When the interaction between NK cells and OP9 cells were inhibited in vitro, IFN-${\gamma}$ production from NK cells were reduced. Conclusion: Based on these observations, it is concluded that Gpnmb has a potential role in NK cell development from HSCs.