The ER membrane protein complex subunit Emc3 controls angiogenesis via the FZD4/WNT signaling axis
The ER membrane protein complex subunit Emc3 controls angiogenesis via the FZD4/WNT signaling axis
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DOI：
10.1007/s11427-021-1941-7
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发表时间：
2021-06-10
影响因子：
9.1
通讯作者：
Zhu, Xianjun
中科院分区：
文献类型：
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作者：
Yang, Mu;Li, Shujin;Zhu, Xianjun
内质网(ER)膜蛋白复合体(EMC)调节具有多个跨膜结构域的膜蛋白的合成和质量控制。EMC3是跨膜的亚基之一，是EMC复合体的核心成员，为底物插入提供必要的亲水性前庭。在这里，我们证明了EMC亚单位Emc3通过调节Norrin/Wnt信号在视网膜血管生成中起关键作用。出生后内皮细胞(EC)特异性缺失Emc3导致视网膜血管发育迟缓，血管网络过度修剪，出现钝端、动脉瘤样的尖端内皮细胞(ECs)，丝状足数量减少，血管前方红细胞渗漏。在EMC3耗竭的人视网膜内皮细胞(HRECs)中也观察到管状形成和细胞增殖减少。然后，我们通过RNA测序、实时定量聚合酶链式反应(RT-qPCR)和荧光素酶报告实验发现，EMC3在β-连环蛋白信号转导的FZD4受体的表达中起着关键作用。此外，经氯化锂(LiCl)处理后，Wnt活性显著增强，β-catenin信号转导和细胞增殖显著增强。此外，氯化锂部分逆转了Emc3-CKO小鼠的血管生成缺陷。我们的数据表明，Emc3通过直接调控FZD4的表达和Norrin/β-catenin信号在血管生成中发挥重要作用。
The endoplasmic reticulum (ER) membrane protein complex (EMC) regulates the synthesis and quality control of membrane proteins with multiple transmembrane domains. One of the membrane spanning subunits, EMC3, is a core member of the EMC complex that provides essential hydrophilic vestibule for substrate insertion. Here, we show that the EMC subunit Emc3 plays critical roles in the retinal vascular angiogenesis by regulating Norrin/Wnt signaling. Postnatal endothelial cell (EC)-specific deletion of Emc3 led to retarded retinal vascular development with a hyperpruned vascular network, the appearance of blunt-ended, aneurysm-like tip endothelial cells (ECs) with reduced numbers of filopodia and leakage of erythrocytes at the vascular front. Diminished tube formation and cell proliferation were also observed in EMC3 depleted human retinal endothelial cells (HRECs). We then discovered a critical role for EMC3 in expression of FZD4 receptor of beta-catenin signaling using RNA sequencing, real-time quantitative PCR (RT-qPCR) and luciferase reporter assay. Moreover, augmentation of Wnt activity via lithium chloride (LiCl) treatment remarkably enhanced beta-catenin signaling and cell proliferation of HRECs. Additionally, LiCl partially reversed the angiogenesis defects in Emc3-cKO mice. Our data reveal that Emc3 plays essential roles in angiogenesis through direct control of FZD4 expression and Norrin/beta-catenin signaling.