Diep Cuong Q, Peng Zhenzhen, Ukah Tobechukwu K, Kelly Paul M, Daigle Renee V, Davidson Alan J
Department of Medicine, Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Medicine, Harvard Medical School, Boston, Massachusetts; Kidney Program, Harvard Stem Cell Institute, Cambridge, Massachusetts; Department of Biology, Indiana University of Pennsylvania, Indiana, Pennsylvania.
Genesis. 2015 Mar-Apr;53(3-4):257-69. doi: 10.1002/dvg.22846. Epub 2015 Mar 14.
The vertebrate kidney plays an essential role in removing metabolic waste and balancing water and salt. This is carried out by nephrons, which comprise a blood filter attached to an epithelial tubule with proximal and distal segments. In zebrafish, two nephrons are first formed as part of the embryonic kidney (pronephros) and hundreds are formed later to make up the adult kidney (mesonephros). Previous studies have focused on the development of the pronephros while considerably less is known about how the mesonephros is formed. Here, we characterize mesonephros development in zebrafish and examine the nephrons that form during larval metamorphosis. These nephrons, arising from proliferating progenitor cells that express the renal transcription factor genes wt1b, pax2a, and lhx1a, form on top of the pronephric tubules and develop a segmentation pattern similar to pronephric nephrons. We find that the pronephros acts as a scaffold for the mesonephros, where new nephrons fuse with the distal segments of the pronephric tubules to form the final branching network that characterizes the adult zebrafish kidney.
脊椎动物的肾脏在清除代谢废物以及平衡水盐方面发挥着至关重要的作用。这一功能由肾单位来执行，肾单位由一个与上皮小管相连的血液过滤器组成，上皮小管有近端和远端部分。在斑马鱼中，最初会形成两个肾单位作为胚胎肾脏（前肾）的一部分，之后会形成数百个肾单位以构成成体肾脏（中肾）。先前的研究主要集中在前肾的发育上，而对于中肾是如何形成的了解则少得多。在这里，我们描述了斑马鱼中肾的发育过程，并研究了在幼体变态期间形成的肾单位。这些肾单位由表达肾转录因子基因wt1b、pax2a和lhx1a的增殖祖细胞产生，形成于前肾小管之上，并发育出与前肾肾单位相似的节段模式。我们发现，前肾作为中肾的支架，新的肾单位与前肾小管的远端部分融合，形成了成年斑马鱼肾脏特有的最终分支网络。
