State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa 999078, Macau SAR, China.
Sino-French Hoffmann Institute, School of Basic Medical Science, State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou 510180, China.
Environ Sci Technol. 2022 Jul 5;56(13):9536-9545. doi: 10.1021/acs.est.2c01307. Epub 2022 May 20.
Covalent modification of proteins by reactive pollutants/metabolites might trigger various toxicities resulting from the disruption of protein structures and/or functions, which is critical for understanding the mechanism of pollutants-induced toxicity. However, this mechanism has rarely been touched on due to the lack of a methodology. In this research, the protein modification of bisphenol A (BPA) in rats was characterized using a series of liquid chromatography-tandem mass spectrometry (LC-MS) approaches. BPA-modified cysteine (Cys1) was first released from proteins via enzymatic hydrolysis and identified using LC-MS. Moreover, the positive correlation between Cys1 and hepatotoxicity indicated the involvement of protein modification in BPA toxicity. Then, in vitro incubation of BPA with amino acids and protein confirmed that BPA could specifically modify cysteine residues of proteins after bioactivation and provided four additional modification patterns. Finally, 24 BPA-modified proteins were identified from the liver of BPA-exposed rats using proteomic analysis, and they were mainly enriched in oxidative stress-related pathways. The modification on superoxide dismutases, catalase, and glutathione S-transferases disrupted their enzymatic functions, leading to oxidative damage. These results revealed that the covalent protein modification is an unignorable factor for BPA hepatotoxicity. Moreover, the workflow can be applied to identify protein adducts of other emerging contaminants and possible risk.
活性污染物/代谢物对蛋白质的共价修饰可能会导致蛋白质结构和/或功能的破坏，从而引发各种毒性，这对于理解污染物诱导毒性的机制至关重要。然而，由于缺乏方法学，这个机制很少被涉及。在这项研究中，使用一系列液相色谱-串联质谱（LC-MS）方法来描述双酚 A（BPA）在大鼠体内的蛋白质修饰。首先通过酶解将 BPA 修饰的半胱氨酸（Cys1）从蛋白质中释放出来，并通过 LC-MS 进行鉴定。此外，Cys1 与肝毒性之间的正相关性表明蛋白质修饰参与了 BPA 的毒性。然后，体外将 BPA 与氨基酸和蛋白质孵育，证实 BPA 可以在生物活化后特异性修饰蛋白质的半胱氨酸残基，并提供了另外四种修饰模式。最后，使用蛋白质组学分析从 BPA 暴露大鼠的肝脏中鉴定出 24 种 BPA 修饰蛋白，它们主要富集在氧化应激相关途径中。对超氧化物歧化酶、过氧化氢酶和谷胱甘肽 S-转移酶的修饰破坏了它们的酶功能，导致氧化损伤。这些结果表明，共价蛋白质修饰是 BPA 肝毒性的一个不可忽视的因素。此外，该工作流程可用于鉴定其他新兴污染物和可能风险的蛋白质加合物。
