Disruption of function and localization of tight junctional structures and Mrp2 in sustained estradiol-17β-D-glucuronide-induced cholestasis
Disruption of function and localization of tight junctional structures and Mrp2 in sustained estradiol-17β-D-glucuronide-induced cholestasis
复制标题
DOI：
10.1152/ajpgi.00496.2006
复制
发表时间：
2007-07-01
影响因子：
4.5
通讯作者：
Vore, Mary
中科院分区：
文献类型：
--
作者：
Mottino, Aldo D.;Hoffman, Tim;Vore, Mary
当以单次推注剂量给药时，雌二醇-17 β-D-葡萄糖醛酸 (E(2)17G) 会在大鼠中诱导立即、严重但短暂的胆汁淤积。在这里，我们检查了持续 E217G 胆汁淤积的后果，并评估了紧密连接蛋白 zonula occlusionns-1 (ZO-1) 和 occludin 以及小管转运蛋白多药耐药相关蛋白 2 (Mrp2) 的功能和定位。 E(2)17G 初始剂量（15 μmol/kg iv），随后在 60 至 240 分钟内连续注射 5 剂 7.5 μmol/kg，导致胆汁流量持续减少 40 - 70%。胆道逆行给药后，在肝窦区域检测到霍乱毒素 B 亚基 - FITC 或辣根过氧化物酶，表明细胞旁途径打开；这种情况早在第一次给药后 15 分钟以及最后一次给药后 15 分钟就发生了，但在对照组中施用媒介物后则没有。 ZO-1和occludin的定位在急性胆汁淤积条件下仅受到轻微影响，但在持续胆汁淤积条件下受到严重破坏，其外观表明结构碎片。单次 E217G 给药后 20 分钟，Mrp2 内吞至肾小管周围区域的现象明显；然而，在持续的胆汁淤积下，Mrp2被发现更深入地内化并部分重新分布到基底外侧膜。总之，急性E(2)17G诱导的胆汁淤积增加了紧密连接的通透性，而持续的胆汁淤积除了增加紧密连接的通透性之外，还引起ZO-1、occludin和Mrp2的显着重新分布。紧密连接完整性的改变可能会导致胆汁分泌受损，并且可能与 Mrp2 定位的变化有因果关系。
Estradiol-17 beta-D-glucuronide (E(2)17G) induces immediate and profound but transient cholestasis in rats when administered as a single bolus dose. Here, we examined the consequence of sustained E217G cholestasis and assessed the function and localization of the tight junctional proteins zonula occludens-1 ( ZO-1) and occludin and of the canalicular transporter multidrug resistance-associated protein-2 ( Mrp2). An initial dose of E(2)17G ( 15 mu mol/ kg iv) followed by five subsequent doses of 7.5 mu mol/ kg from 60 to 240 min induced a sustained 40 - 70% decrease in bile flow. Following their biliary retrograde administration, cholera toxin B subunit- FITC or horseradish peroxidase were detected at the sinusoidal domain, indicating opening of the paracellular route; this occurred as early as 15 min after the first dose as well as 15 min after the last dose of E217G, but not following the administration of vehicle in controls. Localization of ZO-1 and occludin was only slightly affected under acute cholestatic conditions but was severely disrupted under sustained cholestasis, with their appearance suggesting a fragmented structure. Endocytic internalization of Mrp2 to the pericanalicular region was apparent 20 min after a single E217G administration; however, Mrp2 was found more deeply internalized and partially redistributed to the basolateral membrane under sustained cholestasis. In conclusion, acute E(2)17G-induced cholestasis increased permeability of the tight junction, while sustained cholestasis provoked a significant redistribution of ZO-1, occludin, and Mrp2 in addition to increased permeability of the tight junction. Altered tight junction integrity likely contributes to impaired bile secretion and may be causally related to changes in Mrp2 localization.