Embryonic Development of the Mammalian Epididymis

描述（由申请方提供）：附睾对精子成熟过程至关重要，因为它提供了一个独特的管腔流体微环境，允许精子成熟和存活，该功能的中断会导致男性不育。然而，胎儿发育异常也可能导致附睾功能障碍，尽管对附睾发育过程或导致男性不育的先天性缺陷的性质和原因知之甚少。在沃尔夫管/附睾管胚胎发育过程中的一个主要事件是伸长和卷曲，推测是细胞增殖的结果。然而，在本申请中，我们假设另外的机制，细胞嵌入有助于伸长和卷曲。延伸和卷曲不是一个微不足道的事件，但必须与其提供独特的管腔流体微环境的专门功能高度协调，这对精子成熟非常重要。我们选择胚胎时期是因为细胞增殖和导管卷曲开始，这是一个潜在的缺陷可能发生的时间。检查的机制（S）的细胞插入作为一种手段，延长和线圈的沃尔夫管是新颖的，我们特别感兴趣的是检查的贡献的平面细胞极性通路（PCP），Ptk 7，作为一个调节器的这一重要事件在沃尔夫管形态发生。将使用遗传修饰小鼠、现代成像技术、体外器官培养技术和基因修饰方法的组合来测试以下三个具体目标中概述的假设：（1）测试Ptk 7在细胞形状和细胞定位中起重要作用的假设，这反过来又允许沃尔夫管经历伸长和卷曲的形态发生事件。(2)验证Ptk 7在Wolff管胚胎发育过程中通过调节基底外侧细胞的增殖活性和细胞分裂方向而维持细胞增殖，从而调节特定细胞重排的假说。(3)为了检验以下假设：在沃尔夫氏管伸长和卷曲过程中，细胞嵌入是由细胞骨架组织的极化变化驱动的，并通过激活Wnt/PCP通路由Ptk 7调节。总之，沃尔夫氏管可以通过细胞嵌入延长的假设是非常新颖和创新的，因为一直认为附睾管的延长仅通过细胞增殖。此外，我们还发现了一种不寻常的调节分子Ptk 7，假设它在沃尔夫管的伸长和卷曲中发挥作用。这项研究的预期结果不仅将对生殖生物学领域产生重大影响，而且还将有助于我们了解管形态发生的基本过程。具体来说，他们将提供一个了解如何在发展过程中的附睾生长调节是重要的临床。

DESCRIPTION (provided by applicant): The epididymis is critical to the process of sperm maturation because it provides a unique luminal fluid microenvironment that allows for sperm maturation and survival, and disruptions to this function lead to male infertility. However, disruptions to epididymal function may also arise as a consequence of abnormal fetal development, although very little is known either of the process of epididymal development or of the nature and causes of congenital defects that lead to male infertility. A major event during Wolffian/ epididymal duct embryonic development is elongation and coiling, presumably as a result of cell proliferation. However, in this application we hypothesize that an additional mechanism, cell intercalation contributes to elongation and coiling. Elongation and coiling is not a trivial event but must be highly coordinated with its specialized function of providing a unique luminal fluid microenvironment that is so important for sperm maturation. We have chosen the embryonic time period because cell proliferation and ductal coiling are initiated and it is a time when potential defects can occur. Examining the mechanism(s) of cell intercalation as a means to elongate and coil the Wolffian duct is novel, and we are especially interested in examining the contribution of a member of the planar cell polarity pathway (PCP), Ptk7, as a regulator of this important event during Wolffian duct morphogenesis. A combination of genetically modified mice, modern imaging techniques, in vitro organ culture techniques, and gene modifying approaches will be used to test the hypotheses outlined in the following three specific aims: (1) To test the hypothesis that Ptk7 plays an important role in cell shape and cell positioning, which in turn allow the Wolffian duct to undergo the morphogenic events of elongation and coiling. (2) To test the hypothesis that Ptk7 regulates specific cell rearrangements by modulating the basolateral protrusive activity and the orientation of cell division yet maintaining cell proliferaion during Wolffian duct embryonic development. (3) To test the hypothesis that cell intercalation during Wolffian duct elongation and coiling is driven by polarized changes in cytoskeleton organization, and is regulated by Ptk7 through activation of the Wnt/PCP pathway. In summary, the hypothesis that the Wolffian duct can elongate via cell intercalation is highly novel and innovative because it has always been assumed that elongation of the epididymal duct is via cell proliferation only. In addition, we have uncovered an unusual regulatory molecule, Ptk7, which is hypothesized to play a role in Wolffian duct elongation and coiling. The anticipated outcomes of this study will not only have a major impact on an area of reproductive biology that has been poorly understood, but will also contribute to our understanding of the fundamental process of tube morphogenesis. Specifically they will provide an understanding as to how the regulation of growth of the epididymis during development is important clinically.