Sainio K, Raatikainen-Ahokas A
Developmental Biology Programme, Institute of Biotechnology, University of Helsinki, Finland.
Int J Dev Biol. 1999;43(5):435-9.
Mesonephros is a vestige, transient renal organ that functions only during embryonic development. The anatomy, position and even cellular fate of the mesonephric kidney varies drastically among mammalian species. The origin of mesonephros from intermediate mesoderm and the dependence of its differentiation on the nephric or Wolffian duct have been well established. Commonly accepted is also the mesonephric origin of epididymal ducts of the male reproductive tract. Recently, upon the more profound understanding of the molecular mechanisms involved in the development of the permanent mammalian kidney, some light has been shed over the molecular events taking place during the mesonephric development as well. Because of the functional and structural similarities between the mesonephric and metanephric kidneys, it is not surprising that many molecules regulating metanephric development are also activated during mesonephric development. However, the multifunctional nature of mesonephros has been unexpected. First, it serves as an embryonic secretory organ, in some mammalian species more so than in others. It is thereafter removed by programmed cell death. Second, it is a source of multiple stem cells including somatic cells in the male gonad, vascular endothelial cells, and hematopoietic stem cells. Thus, mesonephros is a challenging model for studies on epithelial differentiation and organogenesis, regulation of apoptosis, sex determination and stem cell differentiation. In this review, we focus in the molecular and stem cell aspects in the differentiation of the mammalian mesonephros.
中肾是一种遗迹性的、短暂存在的肾脏器官，仅在胚胎发育期间发挥功能。中肾的解剖结构、位置甚至细胞命运在不同哺乳动物物种之间差异极大。中肾起源于中间中胚层，其分化依赖于肾管或沃尔夫管，这一点已得到充分证实。雄性生殖道附睾管起源于中肾这一点也得到了普遍认可。最近，随着对哺乳动物永久性肾脏发育所涉及分子机制的更深入了解，中肾发育过程中发生的分子事件也有了一些线索。由于中肾和后肾在功能和结构上存在相似性，许多调节后肾发育的分子在中肾发育过程中也被激活也就不足为奇了。然而，中肾的多功能性质却出人意料。首先，它作为一个胚胎分泌器官，在某些哺乳动物物种中比在其他物种中作用更大。此后，它通过程序性细胞死亡被清除。其次，它是多种干细胞的来源，包括雄性性腺中的体细胞、血管内皮细胞和造血干细胞。因此，中肾是上皮分化与器官发生、细胞凋亡调控、性别决定和干细胞分化研究的一个具有挑战性的模型。在这篇综述中，我们聚焦于哺乳动物中肾分化的分子和干细胞方面。
