School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore.
Department of Endocrinology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.
Sci Rep. 2020 Apr 15;10(1):6475. doi: 10.1038/s41598-020-62341-z.
Metabolic disorders in T2DM generate multiple sources of free radicals and oxidative stress that accelerate nonenzymatic degenerative protein modifications (DPMs) such as protein oxidation, disrupt redox signaling and physiological function, and remain a major risk factor for clinical diabetic vascular complications. In order to identify potential oxidative biomarkers in the blood plasma of patients with T2DM, we used LC-MS/MS-based proteomics to profile plasma samples from patients with T2DM and healthy controls. The results showed that human serum albumin (HSA) is damaged by irreversible cysteine trioxidation, which can be a potential oxidative stress biomarker for the early diagnosis of T2DM. The quantitative detection of site-specific thiol trioxidation is technically challenging; thus, we developed a sensitive and selective LC-MS/MS workflow that has been used to discover and quantify three unique thiol-trioxidized HSA peptides, ALVLIAFAQYLQQCPFEDHVK (m/z 1241.13), YICENQDSISSK (m/z 717.80) and RPCFSALEVDETYVPK (m/z 951.45), in 16 individual samples of healthy controls (n = 8) and individuals with diabetes (n = 8). Targeted quantitative analysis using multiple reaction monitoring mass spectrometry revealed impairment of the peptides with m/z 1241.13, m/z 717.80 and m/z 951.45, with significance (P < 0.02, P < 0.002 and P < 0.03), in individuals with diabetes. The results demonstrated that a set of three HSA thiol-trioxidized peptides, which are irreversibly oxidatively damaged in HSA in the plasma of patients with T2DM, can be important indicators and potential biomarkers of oxidative stress in T2DM.
2 型糖尿病中的代谢紊乱会产生多种自由基和氧化应激源，加速非酶促退行性蛋白修饰（DPM），如蛋白质氧化，破坏氧化还原信号和生理功能，仍然是临床糖尿病血管并发症的主要危险因素。为了确定 2 型糖尿病患者血浆中潜在的氧化生物标志物，我们使用基于 LC-MS/MS 的蛋白质组学方法对 2 型糖尿病患者和健康对照者的血浆样本进行了分析。结果表明，人血清白蛋白（HSA）受到不可逆的半胱氨酸三氧化损伤，这可能是 2 型糖尿病早期诊断的潜在氧化应激生物标志物。对特异性硫醇三氧化的定量检测具有技术挑战性；因此，我们开发了一种灵敏且选择性的 LC-MS/MS 工作流程，该流程已用于发现和定量三种独特的硫醇三氧化 HSA 肽，即 ALVLIAFAQYLQQCPFEDHVK（m/z 1241.13）、YICENQDSISSK（m/z 717.80）和 RPCFSALEVDETYVPK（m/z 951.45），在 16 个健康对照者（n = 8）和糖尿病患者（n = 8）的个体样本中。使用多重反应监测质谱进行的靶向定量分析显示，m/z 1241.13、m/z 717.80 和 m/z 951.45 肽的损伤具有统计学意义（P < 0.02、P < 0.002 和 P < 0.03），糖尿病患者中。结果表明，一组三种 HSA 硫醇三氧化肽，在 2 型糖尿病患者血浆中的 HSA 中发生不可逆氧化损伤，可能是 2 型糖尿病氧化应激的重要指标和潜在生物标志物。
