Sacre Sandra M, Moss Stephen E
Department of Cell Biology, Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, United Kingdom.
Exp Cell Res. 2002 Apr 1;274(2):254-63. doi: 10.1006/excr.2002.5469.
Annexins are calcium-dependent phospholipid binding proteins that are implicated in the regulation of both intracellular and extracellular thrombostatic mechanisms in the vascular endothelium. Tight control of annexin gene expression and targeting of annexin proteins is therefore of importance in maintaining the health of the endothelium. Because annexins are abundant in vascular endothelial cells and could be either dysregulated by or contribute to anomalies in Ca2+ signaling, we investigated annexin gene expression and subcellular localization in human umbilical vein endothelial cells (HUVEC) in a model of chronic oxidative stress. HUVEC were cultured under mild hyperoxic conditions in a custom-built chamber to induce oxidative stress over a period of 12 days. Although annexin expression levels did not change significantly in response to hyperoxic stress, immunofluorescence analysis revealed striking effects on the subcellular localization of certain annexins, including the redistribution of annexins 5 and 6 from the cytosol to the nucleus. In addition, oxidative stress modulated the responses of certain annexins to stimulation with a range of pharmacological and physiological Ca2+-mobilizing agonists, in a manner that suggested that annexin localization is regulated via the complex integration of both Ca2+ and intracellular signaling pathways. These results show that differential regulation of annexin localization by oxidative stress may have a causative role in the cellular pathophysiology of vascular endothelial cell disease.
膜联蛋白是一类依赖钙的磷脂结合蛋白，参与血管内皮细胞内和细胞外血栓形成机制的调节。因此，严格控制膜联蛋白基因表达以及膜联蛋白的靶向作用对于维持内皮细胞健康至关重要。由于膜联蛋白在血管内皮细胞中含量丰富，并且可能因Ca2+信号异常而失调或导致异常，我们在慢性氧化应激模型中研究了人脐静脉内皮细胞（HUVEC）中膜联蛋白基因的表达和亚细胞定位。将HUVEC在定制培养箱中于轻度高氧条件下培养12天以诱导氧化应激。尽管膜联蛋白表达水平对高氧应激无明显变化，但免疫荧光分析显示对某些膜联蛋白的亚细胞定位有显著影响，包括膜联蛋白5和6从细胞质重新分布到细胞核。此外，氧化应激以一种提示膜联蛋白定位通过Ca2+和细胞内信号通路的复杂整合来调节的方式，调节了某些膜联蛋白对一系列药理和生理Ca2+动员激动剂刺激的反应。这些结果表明，氧化应激对膜联蛋白定位的差异调节可能在血管内皮细胞疾病的细胞病理生理学中起因果作用。
