造血干細胞存在于骨髓中一個專門的調(diào)控環(huán)境中?，F(xiàn)在，這一小環(huán)境的精確位置和特點因兩項尖端的成像研究而變得更清楚了,。
Lo Celso等人在動物活體中對各個造血干細胞進行了跟蹤,，發(fā)現(xiàn)成骨細胞陷入在由微血管構(gòu)成的網(wǎng)中，不同造血干細胞群根據(jù)它們分化階段的不同而位于不同地方,。Xie等人利用新開發(fā)的“間接體內(nèi)療法”（ex vivo）實時成像技術(shù)和免疫測定對熒光標記的造血干細胞因響應(yīng)輻照而發(fā)生的“尋的”（homing）行為進行了跟蹤研究,。他們報告說，骨髓腔里的薄膜形成一個特殊區(qū)域,，在正常情況下會維持造血干細胞,，但在發(fā)生骨髓損傷時會促使它們增加數(shù)量。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 457, 92-96 (1 January 2009) | doi:10.1038/nature07434
Live-animal tracking of individual haematopoietic stem/progenitor cells in their niche
Cristina Lo Celso1,4, Heather E. Fleming1,4, Juwell W. Wu3,4, Cher X. Zhao1,4, Sam Miake-Lye1, Joji Fujisaki3,4, Daniel C?té3,7, David W. Rowe5, Charles P. Lin3,4 & David T. Scadden1,2,4,6
1 Center for Regenerative Medicine and,
2 Cancer Center,
3 Advanced Microscopy Program, Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA
4 Harvard Stem Cell Institute, 42 Church Street, Cambridge, Massachusetts 02138, USA
5 University of Connecticut Health Center, 663 Farmington Avenue, Farmington, Connecticut 06030, USA
6 Department of Stem Cell and Regenerative Biology, Harvard University, 42 Church Street, Cambridge, Massachusetts 02138, USA
7 Present address: Centre de Recherche Université Laval Robert-Giffard, Département de Physique, Université Laval, Québec, Québec G1J 2G3, Canada.
Stem cells reside in a specialized, regulatory environment termed the niche that dictates how they generate, maintain and repair tissues1, 2. We have previously documented that transplanted haematopoietic stem and progenitor cell populations localize to subdomains of bone-marrow microvessels where the chemokine CXCL12 is particularly abundant3. Using a combination of high-resolution confocal microscopy and two-photon video imaging of individual haematopoietic cells in the calvarium bone marrow of living mice over time, we examine the relationship of haematopoietic stem and progenitor cells to blood vessels, osteoblasts and endosteal surface as they home and engraft in irradiated and c-Kit-receptor-deficient recipient mice. Osteoblasts were enmeshed in microvessels and relative positioning of stem/progenitor cells within this complex tissue was nonrandom and dynamic. Both cell autonomous and non-autonomous factors influenced primitive cell localization. Different haematopoietic cell subsets localized to distinct locations according to the stage of differentiation. When physiological challenges drove either engraftment or expansion, bone-marrow stem/progenitor cells assumed positions in close proximity to bone and osteoblasts. Our analysis permits observing in real time, at a single cell level, processes that previously have been studied only by their long-term outcome at the organismal level.
