Krouwer Vincent J D, Hekking Liesbeth H P, Langelaar-Makkinje Miriam, Regan-Klapisz Elsa, Post Jan Andries
Department of Biomolecular Imaging, Faculty of Science, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
Vasc Cell. 2012 Aug 28;4(1):12. doi: 10.1186/2045-824X-4-12.
Cellular senescence is associated with cellular dysfunction and has been shown to occur in vivo in age-related cardiovascular diseases such as atherosclerosis. Atherogenesis is accompanied by intimal accumulation of LDL and increased extravasation of monocytes towards accumulated and oxidized LDL, suggesting an affected barrier function of vascular endothelial cells. Our objective was to study the effect of cellular senescence on the barrier function of non-senescent endothelial cells.
Human umbilical vein endothelial cells were cultured until senescence. Senescent cells were compared with non-senescent cells and with co-cultures of non-senescent and senescent cells. Adherens junctions and tight junctions were studied. To assess the barrier function of various monolayers, assays to measure permeability for Lucifer Yellow (LY) and horseradish peroxidase (PO) were performed.
The barrier function of monolayers comprising of senescent cells was compromised and coincided with a change in the distribution of junction proteins and a down-regulation of occludin and claudin-5 expression. Furthermore, a decreased expression of occludin and claudin-5 was observed in co-cultures of non-senescent and senescent cells, not only between senescent cells but also along the entire periphery of non-senescent cells lining a senescent cell.
Our findings show that the presence of senescent endothelial cells in a non-senescent monolayer disrupts tight junction morphology of surrounding young cells and increases the permeability of the monolayer for LY and PO.
细胞衰老与细胞功能障碍相关，并且已证实在诸如动脉粥样硬化等与年龄相关的心血管疾病的体内发生。动脉粥样硬化形成伴随着低密度脂蛋白（LDL）在内膜的积聚以及单核细胞向积聚并氧化的LDL的外渗增加，这表明血管内皮细胞的屏障功能受到影响。我们的目的是研究细胞衰老对非衰老内皮细胞屏障功能的影响。
培养人脐静脉内皮细胞直至衰老。将衰老细胞与非衰老细胞以及非衰老细胞与衰老细胞的共培养物进行比较。研究黏附连接和紧密连接。为了评估各种单层的屏障功能，进行了测量荧光素黄（LY）和辣根过氧化物酶（PO）通透性的测定。
由衰老细胞组成的单层的屏障功能受损，这与连接蛋白分布的变化以及闭合蛋白和紧密连接蛋白-5表达的下调相一致。此外，在非衰老细胞与衰老细胞的共培养物中观察到闭合蛋白和紧密连接蛋白-5的表达降低，不仅在衰老细胞之间，而且在衰老细胞周围的非衰老细胞的整个周边也是如此。
我们的研究结果表明，非衰老单层中衰老内皮细胞的存在破坏了周围年轻细胞的紧密连接形态，并增加了单层对LY和PO的通透性。
