Terskikh V V, Vasil'ev A V, Voroteliak E A
Izv Akad Nauk Ser Biol. 2007 May-Jun(3):261-72.
The nature of the stem cell niche and its interaction with stem cells is one of fundamental problems in the biology of stem cells. Stem cell niches are formed during ontogeny. A niche can remain vacant and exist independently of stem cells; however, stem cell self-renewal cannot be maintained for long periods outside of the niche except for particular conditions, e.g., in vitro. A vacant niche can be occupied by excessive or transplanted stem cells and can provide for their functioning. A niche size allows a definite number of stem cells to be maintained. Excessive stem cells either differentiate in the presence of a specific signal or undergo apoptosis in the absence of such signal. Thus, the niches control the number of stem cells in the body and protect it from excessive stem cell proliferation. Under particular conditions, stem cells can leave and return to their niches. Stem cells are retained in the niche by cell-to-cell interactions and adhesion to the extracellular matrix. Both the niches and stem cells arise at a particular ontogenetic stage and are capable of long self-renewal. The development can be described in terms of the formation of stem cells and their niches.
干细胞生态位的性质及其与干细胞的相互作用是干细胞生物学中的基本问题之一。干细胞生态位在个体发育过程中形成。一个生态位可以保持空置状态并独立于干细胞而存在；然而，除了特定条件下，例如在体外，干细胞在生态位之外无法长期维持自我更新。一个空置的生态位可以被过量的或移植的干细胞占据，并能支持它们的功能。生态位的大小允许维持一定数量的干细胞。过量的干细胞要么在特定信号存在时分化，要么在没有这种信号时发生凋亡。因此，生态位控制着体内干细胞的数量，并保护机体免受干细胞过度增殖的影响。在特定条件下，干细胞可以离开并返回它们的生态位。干细胞通过细胞间相互作用和与细胞外基质的黏附而保留在生态位中。生态位和干细胞都在个体发育的特定阶段出现，并且能够长期自我更新。发育过程可以用干细胞及其生态位的形成来描述。
