School of Life Sciences and Technology, Tongji University, Shanghai 200092, China; Taizhou Enze Medical Center (Group), Enze Hospital, No. 1 East of Tongyang Rd., Luqiao District, Taizhou 318050, Zhejiang Province, China.
Taizhou Enze Medical Center (Group), Enze Hospital, No. 1 East of Tongyang Rd., Luqiao District, Taizhou 318050, Zhejiang Province, China.
Mech Dev. 2020 Mar;161:103595. doi: 10.1016/j.mod.2019.103595. Epub 2019 Dec 27.
Claudins are a family of proteins which are the most important components of the tight junctions. The location of Claudins on the renal tubule epithelial determines its paracellular transport characteristics, but whether Claudins have other functions in kidneys remains still unclear. Here, we showed that the transcripts encoding two Claudin family proteins, claudin-7b (cldn-7b) and claudin-h (cldn-h), were expressed in the transporting cells in the zebrafish pronephros. By knocking down of cldn-7b and cldn-h in zebrafish, we showed that these claudins morphants exhibited cystic kidneys accompanied with body curvature. Further analysis showed that down regulation of cldn-7b or cldn-h led to multiple defects in apico-basolateral polarity, cilia morphology and ciliary function in kidney. Moreover, the ciliary defect was confirmed by depletion of Cldn-7b or Cldn-h using CRISPR/Cas9 system. We also showed that both cldn-7b and cldn-h were genetically interacted with a well-known ciliary gene, arl13b. Deletion of arl13b led to curly cilia in the pronephros that phenocopied with cldn-7b and cldn-h morphants. Taken together, our data suggested that the tight junction protein, Cldn-7b and Cldn-h, regulate kidney development and function by affecting cilia morphology.
紧密连接蛋白是由紧密连接最主要的组成部分构成的蛋白家族。 Claudin 蛋白在肾单位上皮细胞中的位置决定了它的细胞旁通透性特点，但 Claudin 蛋白在肾脏中是否具有其他功能尚不清楚。在这里，我们发现 Claudin 家族蛋白 claudin-7b（cldn-7b）和 claudin-h（cldn-h）的转录本在斑马鱼前肾的转运细胞中表达。通过在斑马鱼中敲低 cldn-7b 和 cldn-h，我们发现这些 Claudin 敲低的斑马鱼表现出囊性肾脏和身体弯曲。进一步的分析表明，下调 cldn-7b 或 cldn-h 导致肾脏顶-基底极性、纤毛形态和纤毛功能的多个缺陷。此外，使用 CRISPR/Cas9 系统耗尽 Cldn-7b 或 Cldn-h 证实了纤毛缺陷的存在。我们还发现 cldn-7b 和 cldn-h 都与一个已知的纤毛基因 arl13b 存在遗传相互作用。arl13b 的缺失导致前肾中卷曲的纤毛，与 cldn-7b 和 cldn-h 敲低的斑马鱼表型相似。总之，我们的数据表明，紧密连接蛋白 Cldn-7b 和 Cldn-h 通过影响纤毛形态来调节肾脏的发育和功能。
