Gleiberman Anatoli S, Michurina Tatyana, Encinas Juan M, Roig Jose L, Krasnov Peter, Balordi Francesca, Fishell Gord, Rosenfeld Michael G, Enikolopov Grigori
Howard Hughes Medical Institute, Department of Medicine, University of California at San Diego School of Medicine, La Jolla, CA 92093-0648, USA.
Proc Natl Acad Sci U S A. 2008 Apr 29;105(17):6332-7. doi: 10.1073/pnas.0801644105. Epub 2008 Apr 24.
Adult tissues undergo continuous cell turnover in response to stress, damage, or physiological demand. New differentiated cells are generated from dedicated or facultative stem cells or from self-renewing differentiated cells. Here we describe a different stem cell strategy for tissue maintenance, distinct from that observed for dedicated or facultative stem cells. We report the presence of nestin-expressing adult stem cells in the perilumenal region of the mature anterior pituitary and, using genetic inducible fate mapping, demonstrate that they serve to generate subsets of all six terminally differentiated endocrine cell types of the pituitary gland. These stem cells, while not playing a significant role in organogenesis, undergo postnatal expansion and start producing differentiated progeny, which colonize the organ that initially entirely consisted of differentiated cells derived from embryonic precursors. This generates a mosaic organ with two phenotypically similar subsets of endocrine cells that have different origins and different life histories. These parallel but distinct lineages of differentiated cells in the gland may help the maturing organism adapt to changes in the metabolic regulatory landscape.
成体组织会因应激、损伤或生理需求而持续进行细胞更新。新的分化细胞由特定的或兼性的干细胞产生，或者由自我更新的分化细胞产生。在这里，我们描述了一种不同于特定的或兼性的干细胞所采用的组织维持干细胞策略。我们报告在成熟垂体前叶的管周区域存在表达巢蛋白的成体干细胞，并利用基因诱导命运图谱证明它们可产生垂体所有六种终末分化内分泌细胞类型的亚群。这些干细胞虽然在器官发生中不发挥重要作用，但在出生后会增殖并开始产生分化后代，这些后代会定殖于最初完全由源自胚胎前体的分化细胞组成的器官。这就产生了一个镶嵌器官，其中有两个表型相似但起源和生命史不同的内分泌细胞亚群。腺体内这些平行但不同的分化细胞谱系可能有助于成熟生物体适应代谢调节环境的变化。
