School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia.
Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia.
Biosci Rep. 2021 May 28;41(5). doi: 10.1042/BSR20210427.
Different skin colour among individuals is determined by the varying amount and types of melanin pigment. Melanin is produced in melanocytes, a type of dendritic cell located in the basal layer of the epidermis, through the process of melanogenesis. Melanogenesis consists of a series of biochemical and enzymatic reactions catalysed by tyrosinase and other tyrosinase-related proteins, leading to the formation of two types of melanin, eumelanin and pheomelanin. Melanogenesis can be regulated intrinsically by several signalling pathways, including the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA), stem cell factor (SCF)/c-kit and wingless-related integration site (Wnt)/β-catenin signalling pathways. Ultraviolet radiation (UVR) is the major extrinsic factor in the regulation of melanogenesis, through the generation of reactive oxygen species (ROS). Antioxidants or antioxidant systems, with the ability to scavenge ROS, may decrease melanogenesis. This review focuses on the two main cellular antioxidant systems, the thioredoxin (Trx) and glutathione (GSH) systems, and discusses their roles in melanogenesis. In the Trx system, high levels/activities of thioredoxin reductase (TrxR) are correlated with melanin formation. The GSH system is linked with regulating pheomelanin formation. Exogenous addition of GSH has been shown to act as a depigmenting agent, suggesting that other antioxidants may also have the potential to act as depigmenting agents for the treatment of human hyperpigmentation disorders.
个体之间不同的肤色是由黑色素色素的数量和类型的不同决定的。黑色素是由位于表皮基底层的树突状细胞类型——黑素细胞通过黑色素生成过程产生的。黑色素生成包括一系列由酪氨酸酶和其他与酪氨酸酶相关的蛋白质催化的生化和酶促反应，导致两种类型的黑色素——真黑色素和褐黑色素的形成。黑色素生成可以通过几种信号通路内在调节，包括环磷酸腺苷（cAMP）/蛋白激酶 A（PKA）、干细胞因子（SCF）/c-kit 和无翅相关整合位点（Wnt）/β-连环蛋白信号通路。紫外线辐射（UVR）是调节黑色素生成的主要外在因素，通过产生活性氧物种（ROS）。具有清除 ROS 能力的抗氧化剂或抗氧化系统可能会降低黑色素生成。本综述重点介绍了两种主要的细胞抗氧化系统，即硫氧还蛋白（Trx）和谷胱甘肽（GSH）系统，并讨论了它们在黑色素生成中的作用。在 Trx 系统中，高水平/活性的硫氧还蛋白还原酶（TrxR）与黑色素形成相关。GSH 系统与调节褐黑色素形成有关。已经表明外源性添加 GSH 可以作为一种脱色剂，这表明其他抗氧化剂也可能具有作为人类色素沉着过度疾病治疗的脱色剂的潜力。
