Friedrich C, Zausch E, Sugrue S P, Gutierrez-Ramos J C
Center for Blood Research, Inc and Departments of Genetics and Anatomy and Cellular Biology, Harvard Medical School, Boston, MA 02115, USA.
Blood. 1996 Jun 1;87(11):4596-606.
We dissected the functions of the microenvironment of bone marrow (BM) and fetal liver (FL) at the cellular level by cloning individual stromal calls and characterizing their phenotypical and functional features. Stromal cell clones derived from FL are large in size (mean forward light scatter intensity [mFSC] of 450), express the surface antigen Thy-1 but not Sca-1 and 6 out of 6 are able to differentiate into fat accumulating adipocytes. BM derived stromal cell clones are either small (mFSC of 250) or large (mFSC of 450), express Sca-1 but not Thy-1 and only 2 out of 7 differentiate towards adipocytes. Heterogeneity in terms of vascular adhesion molecule-1, intracellular adhesion molecule-1 and heat stable antigen expression was found among the different cell clones. Functional assays using long- and short-term cocultures of stromal and hematopoietic calls revealed: (1) the capacity of 8 out of 12 stromal cell clones to support the expansion of primitive hematopoietic progenitors (colony forming unit spleen day 12) more than 10 weeks. Fat accumulation but not expression of stem cell factor by stromal cells did correlate with this supportive function. (2) Better support of granulocyte maturation and proliferation by BM- compared to FL-derived stromal cell clones. However, stromal cell clones from both organs expressed macrophage-colony stimulating factor. (3) The ability of 4 out of 12 stromal cell clones (derived from both, FL and BM) to support the expansion of Interleukin-7 dependent pre-B cells from the BM. Pre-B cell growth stimulating factor was not restricted to supporters. (4) Mutual exclusiveness of myeloid and lymphoid support in that a given stromal cell clone supported either pre B-cell or granulocyte expansion. Experiments comparing the support of BM- and FL-derived hematopoietic progenitors showed identical responses of late (B220+/c-kit-) but strikingly different responses of early (B220+/c-kit+) pre-B cells, revealing different proliferation requirements for FL- versus BM- derived early pre-B cells in vitro.
我们通过克隆单个基质细胞并表征其表型和功能特征，在细胞水平上剖析了骨髓（BM）和胎肝（FL）微环境的功能。源自胎肝的基质细胞克隆体积较大（平均前向光散射强度[mFSC]为450），表达表面抗原Thy-1但不表达Sca-1，6个克隆中有6个能够分化为积累脂肪的脂肪细胞。源自骨髓的基质细胞克隆要么体积小（mFSC为250），要么体积大（mFSC为450），表达Sca-1但不表达Thy-1，7个克隆中只有2个向脂肪细胞分化。在不同的细胞克隆中发现了血管黏附分子-1、细胞间黏附分子-1和热稳定抗原表达方面的异质性。使用基质细胞和造血细胞的长期和短期共培养进行的功能分析表明：（1）12个基质细胞克隆中有8个能够在超过10周的时间里支持原始造血祖细胞（第12天脾集落形成单位）的扩增。基质细胞的脂肪积累而非干细胞因子的表达与这种支持功能相关。（2）与源自胎肝的基质细胞克隆相比，源自骨髓的基质细胞克隆对粒细胞成熟和增殖的支持更好。然而，来自两个器官的基质细胞克隆都表达巨噬细胞集落刺激因子。（3）12个基质细胞克隆（源自胎肝和骨髓）中有4个能够支持来自骨髓的白细胞介素-7依赖性前B细胞的扩增。前B细胞生长刺激因子并不局限于具有支持作用的细胞克隆。（4）髓系和淋巴系支持相互排斥，即给定的基质细胞克隆要么支持前B细胞扩增，要么支持粒细胞扩增。比较源自骨髓和胎肝的造血祖细胞所获得支持的实验表明，晚期（B220+/c-kit-）细胞的反应相同，但早期（B220+/c-kit+）前B细胞的反应明显不同，这揭示了体外源自胎肝与源自骨髓的早期前B细胞具有不同的增殖需求。
