Yaniv Isaac, Stein Jerry, Farkas Daniel L, Askenasy Nadir
Frankel Laboratory of Experimental Bone Marrow Transplantation, Center for Stem Cell Research, Department of Pediatric Hematology-Oncology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel 49202.
Stem Cells Dev. 2006 Feb;15(1):4-16. doi: 10.1089/scd.2006.15.4.
Since introduction of the notion of a "niche" that hosts engraftment and activity of hematopoietic cells, there is a massive effort to discover its structure and decipher its function. Our understanding of the niche is continuously changing with reinterpretation of traditional concepts and apprehension of new insights into the biology of hematopoietic cell homing, seeding, and engraftment. Here we discuss some of the early events in hematopoietic stem cell seeding and engraftment and propose a perspective based on visualization of labeled bone marrow cells in real time in vivo. Primary seeding of hematopoietic cells in the bone marrow niches evolves as a complex and dynamic process; however, it follows discrete topological and chronological patterns. Initial seeding occurs on the endosteal surface of the marrow, which includes heterogeneous niches for primary seeding. Several days after transplantation the endosteal niches become more restrictive, hosting primarily mitotically quiescent cells, and gradual centripetal migration is accompanied by engagement in proliferation and differentiation. The hematopoietic niches evolve as heterogeneous three-dimensional microenvironments that are continuously changing over time.
自从引入了支持造血细胞植入和活动的“龛位”这一概念以来，人们付出了巨大努力来探索其结构并解读其功能。随着对传统概念的重新诠释以及对造血细胞归巢、定植和植入生物学新见解的理解，我们对龛位的认识也在不断变化。在此，我们讨论造血干细胞定植和植入过程中的一些早期事件，并基于对体内实时标记骨髓细胞的可视化提出一种观点。造血细胞在骨髓龛位中的初次定植是一个复杂而动态的过程；然而，它遵循离散的拓扑和时间模式。初次定植发生在骨髓的骨内膜表面，这里包含用于初次定植的异质性龛位。移植几天后，骨内膜龛位变得更具限制性，主要容纳有丝分裂静止细胞，向心性逐渐迁移伴随着增殖和分化的参与。造血龛位演变成随时间不断变化的异质性三维微环境。
