DeLay Bridget D, Baldwin Tanya A, Miller Rachel K
Department of Pediatrics, McGovern Medical School, Pediatric Research Center, University of Texas Health Science Center, Houston, TX, United States.
Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States.
Front Physiol. 2019 Feb 26;10:143. doi: 10.3389/fphys.2019.00143. eCollection 2019.
The adult human kidney contains over one million nephrons, with each nephron consisting of a tube containing segments that have specialized functions in nutrient and water absorption and waste excretion. The embryonic kidney of consists of a single functional nephron composed of regions that are analogous to those found in the human nephron, making it a simple model for the study of nephrogenesis. The exocyst complex, which traffics proteins to the cell membrane in vesicles via CDC42, is essential for normal kidney development. Here, we show that the CDC42-GEF, dynamin binding protein (Dnmbp/Tuba), is essential for nephrogenesis in . is expressed in embryo kidneys during development, and knockdown of Dnmbp using two separate morpholino antisense oligonucleotides results in reduced expression of late pronephric markers, whereas the expression of early markers of nephrogenesis remains unchanged. A greater reduction in expression of markers of differentiated distal and connecting tubules was seen in comparison to proximal tubule markers, indicating that Dnmbp reduction may have a greater impact on distal and connecting tubule differentiation. Additionally, Dnmbp reduction results in glomus and ciliary defects. knockout using CRISPR results in a similar reduction of late markers of pronephric tubulogenesis and also results in edema formation in later stage embryos. Overexpression of in the kidney also resulted in disrupted pronephric tubules, suggesting that levels in the developing kidney are tightly regulated, with either increased or decreased levels leading to developmental defects. Together, these data suggest that Dnmbp is required for nephrogenesis.
成年人类肾脏包含超过一百万个肾单位，每个肾单位由一根管子组成，该管子包含在营养物质和水分吸收以及废物排泄方面具有特殊功能的节段。胚胎肾脏由单个功能性肾单位组成，其区域与人类肾单位中的区域类似，这使其成为研究肾发生的简单模型。外小体复合物通过CDC42将蛋白质以囊泡形式运输到细胞膜，对正常肾脏发育至关重要。在此，我们表明CDC42鸟嘌呤核苷酸交换因子、动力蛋白结合蛋白（Dnmbp/Tuba）对胚胎肾脏的肾发生至关重要。Dnmbp在胚胎发育期间在胚胎肾脏中表达，使用两种不同的吗啉代反义寡核苷酸敲低Dnmbp会导致后期原肾标记物的表达减少，而肾发生早期标记物的表达保持不变。与近端小管标记物相比，分化的远端和连接小管标记物的表达下降更为明显，这表明Dnmbp的减少可能对远端和连接小管的分化有更大影响。此外，Dnmbp的减少会导致肾小球和纤毛缺陷。使用CRISPR敲除Dnmbp会导致原肾小管发生后期标记物的类似减少，并且在后期胚胎中还会导致水肿形成。在肾脏中过表达Dnmbp也会导致原肾小管紊乱，这表明发育中的肾脏中Dnmbp的水平受到严格调节，水平升高或降低都会导致发育缺陷。总之，这些数据表明Dnmbp是肾发生所必需的。
