Early segregation of the adrenal cortex and gonad in chicken embryos
Early segregation of the adrenal cortex and gonad in chicken embryos
复制标题
鸡胚胎中肾上腺皮质和性腺的早期分离
DOI：
10.1111/dgd.12389
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Takahashi Yoshiko
中科院分区：
文献类型：
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作者：
Saito Daisuke;Tamura Koji;Takahashi Yoshiko
肾上腺是一个内分泌器官，在应激反应中起着至关重要的作用。这个器官由肾上腺髓质和肾上腺皮质两种组织组成，它们来自不同的胚胎起源。虽然人们普遍认为肾上腺髓质来自神经脊细胞，但肾上腺皮质的起源仍然难以捉摸。此外，肾上腺皮质和性腺这两个主要的类固醇激素产生组织一直被认为是同一来源的，尽管缺乏实验证据。在这项研究中，为了确定肾上腺皮质的起源并将其与性腺的起源进行比较，我们仔细观察了侧板中胚层分裂成两个体腔上皮成分后体腔上皮(CE)的内侧部分，并在它们之间伴随着体腔腔的开口。我们发现早期的内侧CEs由两层厚的上皮样细胞组成，即外层CEs和内层CEs。外CE面向体腔，而内CE与新生血管并列。结合细胞直接标记和早期分子标记，我们发现外CE是性腺的起源，而不是肾上腺皮质的起源。相反，肾上腺皮质似乎来自内CE。因此，当体腔腔打开时，肾上腺皮质和性腺前体细胞已经彼此分离。这项研究为了解肾上腺是如何形成的以及类固醇激素产生组织在发育过程中是如何产生的提供了新的基础。
The adrenal gland is an endocrine organ that plays essential roles in stress responses. This organ consists of two types of tissues, adrenomedulla and adrenocortex, deriving from different embryonic origins. Whereas it is well accepted that the adrenomedulla derives from neural crest cells, the origin of the adrenocortex remains elusive. In addition, the adrenocortex and gonads, two major steroid hormone‐producing tissues, have been thought to share the same origin, although the experimental evidence is lacking. In this study, to identify the origin of adrenocortex and to compare it to that of gonads, we scrutinized the medial portion of the coelomic epithelium (CE) after the lateral plate mesoderm has split into two CE components with a concomitant opening of the coelomic cavity in between them. We found that early medial CE consists of a two‐cell layer‐thick band of epithelial‐like cells, the outer and inner CEs. The outer CE faces the coelomic cavity, whereas the inner CE is juxtaposed to nascent blood vessels. Combining direct cell labeling with early molecular markers, we found that outer CE was the origin of the gonad but not the adrenocortex. The adrenocortex, instead, appears to derive from inner CE. Thus, the adrenocortical and gonadal progenitors are already segregated from each other when the coelomic cavity has opened. This study provides a new basis for understanding how the adrenal gland forms and how steroid hormone‐producing tissues arise during development.