Slc45a2调控小鼠黑色素细胞色素生成

Slc45a2 Regulates Melanogenesis in Mouse Melanocytes

膜相关转运蛋白Slc45a2(solute carrier family 45 member 2)调节黑素体中的p H值,进而调节酪氨酸酶活性,在黑色素生成中发挥重要作用。小眼畸形转录因子(microphthalmia-associated transcription factor,MITF)已被证实是Slc45a2的调节因子,然而其调控机制仍待研究。该研究旨在探讨Slc45a2在不同毛色小鼠皮肤是否存在差异表达,以及与毛色形成是否存在相关性。QRTPCR检测显示,Slc45a2在不同毛色小鼠皮肤样品中均有表达,在棕色和灰色小鼠皮肤中Slc45a2的表达量是黑色小鼠皮肤的6.29倍(P<0.01)和1.18倍(P<0.05);Western印迹结果显示,在棕色和灰色小鼠皮肤中Slc45a2蛋白表达量是黑色小鼠皮肤的1.44(P<0.01)和1.03倍;免疫组织化学结果表明,Slc45a2在不同毛色皮肤毛囊的毛基质、内外毛根鞘、毛乳头等区域均有表达。为了进一步了解Slc45a2在黑色素细胞色素沉着的重要作用,将Slc45a2转染到小鼠黑色素细胞并测定黑色素含量,同时检测色素沉着相关基因的表达水平。结果表明,转染Slc45a2与空载组相比黑色素含量明显增加。此外,MITF、TYR、TYRP1和TYRP2蛋白水平分别升高1.31倍、1.37倍、1.63倍和2.21倍,差异显著(P<0.05);TYRP2蛋白显著升高2.47倍(P<0.01)。MITF mRNA显著升高1.64(P<0.05);TYR和TYRP1 mRNA显著升高2.96倍(P<0.01)和8.85倍(P<0.01);TYRP2 mRNA表达量变化不明显。Slc45a2在不同毛色小鼠皮肤中均可有效表达,且差异显著。Slc45a2过量表达,使色素沉着相关基因的表达量及黑色素含量增加。由此表明,Slc45a2通过调控色素的生成,进而影响毛色的形成。

The Slc45a2 （solute carrier family 45 member 2 ）, a membrane-associated transporter protein, plays an important role in melanogenesis by regulating the pH value that influences tyrosinase activity of melanosomes. Microphthalmia-associated transcription factor （MITF） has been proved to be a Slc45a2 regulatory factor, but the regulation mechanism remains unclear. This study aimed to investigate whether Slc45a2 is differentially expressed in the skin of mice with various coat colors and determine its correlation with coat color in mice. QRT-PCR analysis revealed that Slc45a2 mRNA was expressed in all skin samples, the relative expression of Slc45a2 mRNA in brown and grey mouse were 6. 29 times （P 〈 0.01） and 1. 18 times （P 〈0.05） when compared to black mice, respectively. Western blot analysis showed that the relative expression of Slc45a2 protein in the skin of brown and grey mice were 1.44 times （P 〈0.01 ） and 1.03 times compared to black mice, respectively. Immunohistochemical assays revealed that Slc45a2 was expressed in the hair follicle matrix, the inner and outer root sheath, and the dermal papilla in the skin with various coat colors. To further investigate the important role of Slc45a2 in pigmentation, we transfected the Slc45a2 into mice melanocytes and then tested the melanin content of melanocytes. Simultaneously, the relative expression levels of pigmentation-related genes were detected. As a result, the melanin content was significantly increased after transfecting Slc45a2 into mice melanocytes in vitro （P 〈 0.01 ）. Furthermore, MITF mRNA was significantly increased to 1.64 times （P 〈0.05） ; TYR and TYRP1 mRNA were significantly increased to 2.96 times （P 〈0.01 ） and 8.85 times （P 〈 0.01 ）; TYRP2 mRNA did not change significantly. MITF, TYR, TYRP1 and TYRP2 proteins were significantly increased to 1.31 times, 1.37 times, 1.63 times and 2.21 times respectively （P 〈0.05）. Slc45a2 was effectively expressed in various coat color skin, and its expression levels had significant differences, and over-expressing Slc45a2 increased the expression level of pigmentation-related genes and melanin content. In summary, Slc45a2 affects coat color by rezulating melanozenesis.