FLT4 调控羊驼黑色素细胞中黑色素生成

血管内皮素生长因子受体3（vascular endothelial growth factor receptor 3,VEGFR-3/FLT4）与黑色素瘤细胞的生长有关，其可能对毛色及黑色素生成有一定的调控作用。为探讨FLT4基因对羊驼毛色及黑色素生成的影响，本文采用免疫组织化学、qRT-PCR、Western印迹对FLT4在不同毛色羊驼皮肤毛囊中的表达进行了研究。结果显示，FLT4在不同毛色毛囊中外根鞘及毛乳头阳性表达不同，且棕色皮肤比白色皮肤阳性信号强；FLT4 mRNA在棕色羊驼皮肤的表达量明显高于白色羊驼皮肤 (P<0.01)；FLT4蛋白在棕色皮肤中的表达量明显高于白色皮肤(P<0.01)；为进一步研究FLT4对黑色素生成的影响；通过对体外培养的羊驼皮肤黑色素细胞中添加不同浓度的FLT4蛋白（0, 1, 10, 50, 100 ng/mL），与对照组相比，添加FLT4蛋白后酪氨酸酶(TYR)、酪氨酸相关蛋白-1(TYRP1)、受体酪氨酸激酶 c-KIT、小眼畸形相关转录因子(MITF)的 mRNA和蛋白质表达明显增加， 10 ng/mL组表达量最高(P<0.01)；黑色素含量测定结果表明，不同浓度的FLT4蛋白处理的羊驼皮肤黑色素细胞的黑色素含量比对照组明显升高，添加FLT4蛋白10 ng/mL表达量最高(P<0.01)。由此可知，FLT4可以通过调节毛色相关基因的表达进而引起黑色素细胞中黑色素含量的变化。

FLT4 Regulates Melanogenesis in Alpaca Melanocytes

Vascular endothelial growth factor receptor (VEGFR 3, FLT4) is related to the growth of melanoma cells, which suggests that FLT4 may be involved in melanogenesis. In order to investigate the effect of FLT4 gene on melanogenesis, immunohistochemistry, qRT-PCR and Western blotting methods were used. The result of immunohistochemistry showed that FLT4 was expressed in the out root sheath and dermal papilla of skins with different coat color. qRT-PCR and Western blotting results showed that the levels of mRNA and protein expression of FLT4 were significantly higher in alpaca skin with brown hair color than that in alpaca skins with white hair color (P<0.01). In vitro, the alpaca melanocytes were cultured with different does of FLT4 (0, 1, 10, 50, 100 ng/mL). The levels of mRNA and protein expression of related hair color genes were examined by qRT-PCR and Western blotting. The results showed that compared with the control group, the levels of TYR, c-KIT, TYRP1 and MITF mRNA and protein expression were increased significantly, and the expression levels were highest at the addition does of 10 ng/mL(P<0.01). The melanin assay results showed that compared with control group, melanocytes production was significantly higher, and the production of melanin was highest at the addition does of 10 ng/mL (P<0.01). The above results suggested that FLT4 may have a functional role in the melanogenesis by correlating the expression of hair color related genes.