Department of Genetics, Coverdell Center, 500 DW Brooks Drive, University of Georgia, Athens, GA 30602, USA.
Front Biosci (Landmark Ed). 2011 Jun 1;16(7):2461-77. doi: 10.2741/3866.
Organs are more than the sum of their component parts--functional competence requires that these parts not only be present in the appropriate proportions, but also be arranged and function together in specific ways. The thymus is an excellent example of the connection between cellular organization and organ function. Unlike more familiar organs, such as lung or kidney, the thymus is not organized into easily identifiable structures such as tubes and ordered cell layers, but instead is a complex meshwork of microenvironments through which T cell progenitors migrate, receiving signals that instruct them to differentiate, proliferate, or die. Proper thymic organization is essential to the optimal production of a functional T cell repertoire. During aging, the thymus undergoes involution, largely due to degradation of the TEC microenvironmental compartment, which then fails to support optimal thymocyte development resulting in reduced output of naive T cells. This review will summarize the current state of understanding of the composition and organization of thymic microenvironments and the mechanisms that promote their proper development and function.
器官不仅仅是其组成部分的总和——功能的实现需要这些部分不仅以适当的比例存在，而且还要以特定的方式排列和共同作用。胸腺就是细胞组织和器官功能之间联系的一个极好的例子。与肺或肾脏等更熟悉的器官不同，胸腺没有组织成易于识别的结构，如管腔和有序的细胞层，而是一个复杂的微环境网络，T 细胞前体细胞在其中迁移，接收信号指导它们分化、增殖或死亡。适当的胸腺组织对于产生功能性 T 细胞库至关重要。随着年龄的增长，胸腺发生萎缩，主要是由于 TEC 微环境隔室的退化，然后无法支持最佳的胸腺细胞发育，导致幼稚 T 细胞的产生减少。这篇综述将总结目前对胸腺微环境组成和组织以及促进其正常发育和功能的机制的理解状态。
