Delta-like ligand 4/DLL4 regulates the capillarization of liver sinusoidal T endothelial cell and liver fibrogenesis
Delta-like ligand 4/DLL4 regulates the capillarization of liver sinusoidal T endothelial cell and liver fibrogenesis
复制标题
Delta样配体4/DLL4调节肝窦T内皮细胞毛细血管化和肝纤维化
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
陆伦根
中科院分区：
文献类型：
--
作者：
陈柳莹;顾天翊;李兵航;李飞;马振增;张启迪;蔡晓波;陆伦根
肝窦内皮细胞（LSECs）在肝纤维化进展过程中发生毛细血管化，即窗孔缺失，并产生基底膜。DLL4是Notch信号通路的一种配体，主要在内皮细胞中表达，并维持肝窦内稳态。本研究的目的是探讨DLL4在LSEC毛细血管化中的作用。通过免疫组织化学、免疫荧光、逆转录 - 聚合酶链反应（RT - PCR）和免疫印迹等适当方法评估DLL4及相关基因、毛细血管化标志物和基底膜蛋白的表达水平。通过电子显微镜检查窗孔和基底膜的形成。我们发现，在人类和四氯化碳（CCl₄）诱导的小鼠纤维化肝脏的LSECs中，DLL4表达上调，这与LSEC毛细血管化和肝纤维化一致。原代小鼠LSECs在体外也会发生毛细血管化，同时伴有DLL4过表达。生物信息学分析证实，DLL4诱导LSECs产生基底膜蛋白，在接受CCl₄处理4周和6周的小鼠的LSECs中，基底膜蛋白也增加。DLL4过表达还通过内皮素 - 1（ET - 1）的合成增加了肝星状细胞（HSCs）对肝窦的覆盖。缺氧条件有助于驱动LSECs中DLL4的过表达。与上述发现一致，体内DLL4沉默缓解了LSEC毛细血管化和CCl₄诱导的肝纤维化。总之，DLL4介导LSEC毛细血管化以及纤维化和病理性肝窦重塑之间的恶性循环。
Liver sinusoidal endothelial cells (LSECs) undergo capillarization, or loss of fenestrae, and produce basement membrane during liver fibrotic progression. DLL4, a ligand of the Notch signaling pathway, is predominantly expressed in endothelial cells and maintains liver sinusoidal homeostasis. The aim of this study was to explore the role of DLL4 in LSEC capillarization. The expression levels of DLL4 and the related genes, capillarization markers and basement membrane proteins were assessed by immunohistochemistry, immunofluorescence, RT- PCR and immunoblotting as appropriate. Fenestrae and basement membrane formation were examined by electron microscopy. We found DLL4 was up-regulated in the LSECs of human and CCl4-induced murine fibrotic liver, consistent with LSEC capillarization and liver fibrosis. Primary murine LSECs also underwent capillar- ization in vitro, with concomitant DLL4 overexpression. Bioinformatics analysis confirmed that DLL4 induced the production of basement membrane proteins in LSECs, which were also increased in the LSECs from 4 and 6-week CCl4-treated mice. DLL4 overexpression also increased the coverage of liver sinusoids by hepatic stellate cells (HSCs) through endothelin-1 (ET-1) synthesis. The hypoxic conditions that was instrumental in driving DLL4 overexpression in the LSECs. Consistent with the above findings, DLL4 silencing in vivo alleviated LSEC ca- pillarization and CCl4-induced liver fibrosis. In conclusion, DLL4 mediates LSEC capillarization and the vicious circle between fibrosis and pathological sinusoidal remodeling.