Tyrosinase is regarded as an important biomarker of melanoma cancer, and its metabolism is closely related to some severe skin diseases such as vitiligo. Since tyrosinase is mainly located in the melanosomes of melanocytes, a probe that can specifically detect and image tysosinase in melanosomes would be in urgent demand to study the behavior of the enzyme in cells, but unfortunately, no melanosome-targeting tyrosinase fluorescent probe has been reported so far to the best of our knowledge. In this work, we have developed such a new probe, Mela-TYR, which bears morpholine as a melanosome-targeting group and 4-aminophenol as a tyrosinase reaction group. The probe exhibits not only a highly sensitive and selective off-on response to tyrosinase via oxidization cleavage, but also an accurate targeting ability toward the acidic organelles of melanosomes and lyososomes, which is validated by colocalization experiments with mCherry-tagged melanosomes as well as DND-99 (a commercial dye). The probe has been used to image the relative contents of tyrosinase in different cells. Notably, because of the tyrosinase deficiency in normal lysosomes, the probe only fluoresces in melanosomes in principle although it can accumulate in other acidic organelles like lysosomes. By virtue of this property, the misdistribution of tyrosinase from melanosomes to lysosomes in murine melanoma B16 cells under the stimulation of inulavosin is imaged in real time for the first time. Moreover, the upregulation of melanosomal tyrosinase in live B16 cells under the stimulation of psoralen/ultraviolet A is detected with our probe, and this upregulation is further verified by standard colorimetric assay. The probe provides a simple, visual method to study the metabolism of tyrosinase in cells and shows great potential in clinical diagnosis and treatments of tyrosinase-associated diseases.
酪氨酸酶被认为是
黑色素瘤癌症的重要
生物标志物,其代谢与白癜风等严重皮肤病密切相关。由于
酪氨酸酶主要位于
黑色素细胞的
黑色素体中,因此急需一种能特异性检测
黑色素体中的
酪氨酸酶并对其成像的探针来研究该酶在细胞中的行为,但遗憾的是,据我们所知,迄今为止还没有关于
黑色素体靶向
酪氨酸酶荧光探针的报道。在这项工作中,我们开发出了这样一种新探针--Mela-TYR,它带有吗啉作为
黑色素体靶向基团,4-
氨基苯酚作为
酪氨酸酶反应基团。该探针不仅对
酪氨酸酶的氧化裂解反应具有高灵敏度和选择性,而且对
黑色素体和溶酶体的酸性细胞器具有准确的靶向能力,这一点通过与mCherry标记的
黑色素体以及DND-99(一种商用
染料)的共定位实验得到了验证。该探针已被用于成像不同细胞中
酪氨酸酶的相对含量。值得注意的是,由于正常溶酶体中缺乏
酪氨酸酶,虽然探针可以在溶酶体等其他酸性细胞器中积聚,但原则上只在
黑色素体中发出荧光。利用这一特性,我们首次实时成像了小鼠
黑色素瘤 B16 细胞在乌拉沃辛刺激下
酪氨酸酶从黑色体向溶酶体的错误分布。此外,在
补骨脂素/紫外线 A 的刺激下,我们的探针还能检测到活体 B16 细胞中
黑色素体
酪氨酸酶的上调,并通过标准比色法进一步验证了这种上调。该探针为研究细胞中
酪氨酸酶的代谢提供了一种简单、直观的方法,在
酪氨酸酶相关疾病的临床诊断和治疗中显示出巨大的潜力。