Endothelial Tight Junctions Are Opened in Cholinergic-Evoked Salivation In Vivo
Endothelial Tight Junctions Are Opened in Cholinergic-Evoked Salivation In Vivo
复制标题
体内胆碱能诱发流涎时内皮紧密连接打开
DOI：
10.1177/0022034516685048
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发表时间：
2017-05-01
影响因子：
7.6
通讯作者：
Wu, L. L.
中科院分区：
文献类型：
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作者：
Cong, X.;Zhang, Y.;Wu, L. L.
血管为初级唾液的形成提供原始供应，初级唾液的形成受内皮细胞之间的紧密连接（TJ）的调节。先前的研究表明，在胆碱能诱发的流涎过程中，血流量随着血管舒张而增加。然而，血管旁细胞通透性的变化和内皮TJ在流涎中的作用尚不清楚。在这里，我们建立了一个在体内细胞旁通透性检测系统，并观察到内皮TJ渗透到4-kDa的异硫氰酸荧光素（FITC）-葡聚糖，而不可渗透到40-和70-kDa的FITC-葡聚糖在小鼠下颌下腺（SMG）的非刺激条件下。毛果芸香碱增加了4-和40-kDa的FITC-葡聚糖的流量出血管，但不影响70-kDa的FITC-葡聚糖。Claudin 5是一种特异性定位于唾液内皮细胞的TJ蛋白，在胆碱能刺激的小鼠SMG和新鲜培养的人SMG组织中，Claudin 5从顶外侧膜重新分布到侧膜和基底外侧膜和细胞质。在从溢泪患者移植的SMG中，我们发现claudin 5存在于基底外侧膜和细胞质中，而不是对照SMG的顶端区域。此外，磷酸肌球蛋白轻链2的水平增加的血管内的匹鲁卡品刺激的小鼠SMG和移植的人SMG，而下游分子F-肌动蛋白重组的内皮细胞移植的人SMG。两者合计，我们的研究结果提供了直接的视觉证据，开放的内皮TJ和claudin 5的重新分配是必不可少的事件，有助于胆碱能诱发的流涎，从而丰富了我们的分泌机制，连接血流的初级唾液形成通过调节内皮细胞旁的渗透性的理解。
Blood vessels provide the original supplies for the formation of primary saliva, which is regulated by the tight junctions (TJs) between endothelial cells. Previous studies have shown that blood flow increases with vasodilatation during cholinergic-evoked salivation. However, changes in vascular paracellular permeability and the role of endothelial TJs in salivation are unknown. Here, we established an in vivo paracellular permeability detection system and observed that the endothelial TJs were permeable to 4-kDa fluorescein isothiocyanate (FITC)–dextran while impermeable to 40- and 70-kDa FITC-dextran under an unstimulated condition in mouse submandibular glands (SMGs). Pilocarpine increased the flux of 4- and 40-kDa FITC-dextran out of blood vessels but did not affect 70-kDa FITC-dextran. Claudin 5, a TJ protein specifically localized in salivary endothelial cells, was redistributed from the apicolateral membranes to the lateral and basolateral membranes and cytoplasm in cholinergic-stimulated mouse SMGs and freshly cultured human SMG tissues. In the transplanted SMGs from epiphora patients, we found that claudin 5 was present in the basolateral membranes and cytoplasm, instead of the apical region in control SMGs. Moreover, the level of phospho–myosin light chain 2 increased within the blood vessels of the pilocarpine-stimulated mouse SMGs and transplanted human SMGs, while the downstream molecule F-actin was reorganized in the endothelial cells of the transplanted human SMGs. Taken together, our findings provide direct visual evidence that the opening of endothelial TJs and the redistribution of claudin 5 are essential events contributing to cholinergic-evoked salivation, thus enriching our understanding of the secretory mechanisms that link blood flow to primary saliva formation by regulating the endothelial paracellular permeability.