Proteome analysis of irradiated endothelial cells reveals persistent alteration in protein degradation and the RhoGDI and NO signalling pathways

<b>Purpose:</b> Epidemiological studies indicate that radiation doses as low as 0.5 Gy increase the risk of cardiovascular disease decades after the exposure. The aim of the present study was to investigate whether this radiation dose causes late molecular alterations in endothelial cells that could support the population-based data. <b>Materials and methods:</b> Human coronary artery endothelial cells were irradiated at 0.5 Gy (X-ray) and radiation-induced changes in the proteome were investigated after different time intervals (1, 7 and 14 d) using ICPL technology. Key changes identified by proteomics and bioinformatics were validated by immunoblotting and ELISA. <b>Results:</b> The radiation-induced alteration of the endothelial proteome was characterized by sustained perturbation of Rho GDP-dissociation inhibitor (RhoGDI) and nitric oxide (NO) signalling pathways. At later time-points, this was accompanied by reduced proteasome activity, enhanced protein carbonylation indicating augmented oxidative stress, and senescence. <b>Conclusions:</b> These molecular changes are indicative of long-term premature endothelial dysfunction and provide a mechanistic framework to the epidemiological data showing increased risk of cardiovascular disease at 0.5 Gy. Watch the video on YouTube

一、研究目的：流行病学研究表明，即便辐射暴露剂量低至0.5戈瑞（Gy），暴露数十年后受试者的心血管疾病风险仍会显著升高。本研究旨在探究该辐射剂量是否会引发内皮细胞出现迟发性分子改变，从而为人群队列研究的相关数据提供机制层面的支撑。
二、材料与方法：采用X射线以0.5 Gy剂量照射人冠状动脉内皮细胞，在照射后的1天、7天及14天三个时间节点，利用同位素编码蛋白标记（ICPL）技术分析辐射诱导的蛋白质组变化；并通过免疫印迹法与酶联免疫吸附试验（ELISA），对蛋白质组学及生物信息学鉴定得到的关键变化进行验证。
三、研究结果：辐射诱导的内皮细胞蛋白质组改变以Rho GDP解离抑制剂（RhoGDI）与一氧化氮（NO）信号通路的持续紊乱为核心特征。在后续较晚的时间节点中，该蛋白质组变化伴随蛋白酶体活性降低、蛋白质羰基化水平升高（提示氧化应激增强）以及细胞衰老现象的出现。
四、研究结论：上述分子变化提示存在长期早发性内皮功能障碍，可为流行病学研究中“0.5 Gy辐射暴露会升高心血管疾病风险”的结论提供系统性的机制理论框架。可在YouTube平台观看相关视频