目的:应用基于串联质量标签(TMT)的LC-MS/MS分析筛选脑干创伤性轴索损伤(TAI)中的差异表达蛋白(DEP),并预测潜在的生物标志物和关键分子机制脑干TAI。
方法:采用改良的冲击加速度损伤模型建立Sprague-Dawley大鼠脑干TAI模型,并根据功能变化(生命体征测量)和结构变化(HE染色,镀银染色和β-APP免疫组织化学染色)。TMT联合LC-MS/MS分析TAI和Sham组脑干组织中的DEP。通过生物信息学技术分析了DEP在TAI超急性期的生物学功能和潜在的分子机制。和候选生物标志物使用免疫印迹和免疫组织化学对来自动物模型和人类的脑干组织进行验证。
结果:在成功建立大鼠脑干TAI模型的基础上,基于TMT的蛋白质组学鉴定了65个DEP,和生物信息学分析表明,TAI的超急性期涉及多个阶段的生物过程,包括炎症,氧化应激,能量代谢,神经元兴奋性毒性和细胞凋亡。三个部门,选择CBR1、EPHX2和CYP2U1作为候选生物标志物,并且发现所有三种蛋白质在动物模型和人类中TAI后30分钟-7天在脑干组织中显著表达。
结论:使用TMT结合LC-MS/MS分析进行早期大鼠脑干TAI的蛋白质组学研究,我们首次报道CBR1、EPHX2和CYP2U1可作为脑干早期TAI的生物标志物,弥补了镀银染色和β-APP免疫组织化学染色的局限性,特别是在TAI后存活时间非常短(短于30分钟)的情况下。还提出了许多其他具有潜在标记作用的蛋白质,提供对分子机制的新见解,脑干早期TAI的治疗靶点和法医学鉴定。
OBJECTIVE: Application of Tandem Mass Tags (TMT)-based LC-MS/MS analysis to screen for differentially expressed proteins (DEPs) in traumatic axonal injury (TAI) of the brainstem and to predict potential biomarkers and key molecular mechanisms of brainstem TAI.
METHODS: A modified impact acceleration injury model was used to establish a brainstem TAI model in Sprague-Dawley rats, and the model was evaluated in terms of both functional changes (vital sign measurements) andstructural changes (HE staining, silver-plating staining and β-APP immunohistochemical staining). TMT combined with LC-MS/MS was used to analyse the DEPs in brainstem tissues from TAI and Sham groups. The biological functions of DEPs and potential molecular mechanisms in the hyperacute phase of TAI were analysed by bioinformatics techniques, and candidate biomarkers were validated using western blotting and immunohistochemistry on brainstem tissues from animal models and humans.
RESULTS: Based on the successful establishment of the brainstem TAI model in rats, TMT-based proteomics identified 65 DEPs, and bioinformatics analysis indicated that the hyperacute phase of TAI involves multiple stages of biological processes including inflammation, oxidative stress, energy metabolism, neuronal excitotoxicity and apoptosis. Three DEPs, CBR1, EPHX2 and CYP2U1, were selected as candidate biomarkers and all three proteins were found to be significantly expressed in brainstem tissue 30 min-7 days after TAI in both animal models and humans.
CONCLUSIONS: Using TMT combined with LC-MS/MS analysis for proteomic study of early TAI in rat brainstem, we report for the first time that CBR1, EPHX2 and CYP2U1 can be used as biomarkers of early TAI in brainstem by means of western blotting and immunohistochemical staining, compensating for the limitations of silver-plating staining and β-APP immunohistochemical staining, especially in the case of very short survival time after TAI (shorter than 30 min). A number of other proteins that also have a potential marker role are also presented, providing new insights into the molecular mechanisms, therapeutic targets and forensic identification of early TAI in brainstem.