Department of Pediatrics, Pediatric Research Center, UTHealth McGovern Medical School, Houston, Texas, United States of America.
MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genes and Development, Houston, Texas, United States of America.
PLoS One. 2019 Aug 30;14(8):e0221698. doi: 10.1371/journal.pone.0221698. eCollection 2019.
Kidneys are composed of numerous ciliated epithelial tubules called nephrons. Each nephron functions to reabsorb nutrients and concentrate waste products into urine. Defects in primary cilia are associated with abnormal formation of nephrons and cyst formation in a wide range of kidney disorders. Previous work in Xenopus laevis and zebrafish embryos established that loss of components that make up the Wnt/PCP pathway, Daam1 and ArhGEF19 (wGEF) perturb kidney tubulogenesis. Dishevelled, which activates both the canonical and non-canonical Wnt/PCP pathway, affect cilia formation in multiciliated cells. In this study, we investigated the role of the noncanoncial Wnt/PCP components Daam1 and ArhGEF19 (wGEF) in renal ciliogenesis utilizing polarized mammalian kidney epithelia cells (MDCKII and IMCD3) and Xenopus laevis embryonic kidney. We demonstrate that knockdown of Daam1 and ArhGEF19 in MDCKII and IMCD3 cells leads to loss of cilia, and Daam1's effect on ciliogenesis is mediated by the formin-activity of Daam1. Moreover, Daam1 co-localizes with the ciliary transport protein Ift88 and is present in cilia. Interestingly, knocking down Daam1 in Xenopus kidney does not lead to loss of cilia. These data suggests a new role for Daam1 in the formation of primary cilia.
肾脏由称为肾单位的众多纤毛上皮小管组成。每个肾单位的功能是将营养物质重吸收并将废物浓缩到尿液中。初级纤毛的缺陷与肾单位的异常形成和广泛的肾脏疾病中的囊肿形成有关。先前在非洲爪蟾和斑马鱼胚胎中的研究表明，构成 Wnt/PCP 途径的成分 Daam1 和 ArhGEF19（wGEF）的缺失会破坏肾小管发生。激活经典和非经典 Wnt/PCP 途径的 Dishevelled 会影响多纤毛细胞中的纤毛形成。在这项研究中，我们利用极化的哺乳动物肾上皮细胞（MDCKII 和 IMCD3）和非洲爪蟾胚胎肾研究了非经典 Wnt/PCP 成分 Daam1 和 ArhGEF19（wGEF）在肾纤毛发生中的作用。我们证明，在 MDCKII 和 IMCD3 细胞中敲低 Daam1 和 ArhGEF19 会导致纤毛丧失，并且 Daam1 对纤毛发生的影响是由 Daam1 的形成素活性介导的。此外，Daam1 与纤毛转运蛋白 Ift88 共定位，并存在于纤毛中。有趣的是，在非洲爪蟾肾脏中敲低 Daam1 不会导致纤毛丧失。这些数据表明 Daam1 在初级纤毛形成中具有新的作用。
