Slack J L, Nemunaitis J, Andrews D F, Singer J W
Department of Medicine, University of Washington, Seattle.
Blood. 1990 Jun 15;75(12):2319-27.
Marrow stromal cells are thought to regulate hematopoiesis by producing colony-stimulating factors (CSFs) and other cytokines, either constitutively or in response to mediators such as interleukin-1 alpha (IL-1 alpha) or tumor necrosis factor-alpha (TNF alpha). The mechanisms by which these inflammatory cytokines induce CSF expression in stromal cells are not fully defined. In this study, we used human marrow stromal cells transformed by simian virus 40 (SV-MSCs) to study growth factor and cytokine gene regulation in response to IL-1 alpha and TNF alpha. IL-1 alpha induced significant and prolonged increases in steady-state mRNA levels for interleukin-6 (IL-6), interleukin-1 beta (IL-1 beta), granulocyte-macrophage CSF (GM-CSF), and, to a lesser extent, granulocyte-CSF (G-CSF); this induction was not dependent on new protein synthesis. Nuclear run-on analyses showed that IL-1 alpha transcriptionally activated the genes for IL-6, GM-CSF, and IL-1 beta, while TNF alpha transcriptionally induced expression of IL-6 and IL-1 beta. Furthermore, mRNA for IL-6 and IL-1 beta was dramatically superinduced by the combination of cycloheximide and TNF alpha. When SV-MSCs were cultured in semisolid medium, they formed colonies of blast-like cells that, when replated on plastic, resumed adherent growth. These "colony-derived" cell lines, unlike the parental SV-MSCs from which they were derived, constitutively expressed colony-stimulating activity and mRNA for GM-CSF, G-CSF, IL-6, and IL-1 beta. In this report, we show that the expression of IL-6 and IL-1 beta mRNA in the colony-derived cell lines was due, at least in part, to constitutive transcriptional activation of these genes (similar to the findings in IL-1 alpha- and/or TNF alpha-stimulated parental SV-MSCs). However, in contrast to the transcriptional activation of the GM-CSF gene seen in cytokine-induced parental SV-MSCs, GM-CSF transcripts accumulated in the colony-derived cell lines by a posttranscriptional mechanism.
骨髓基质细胞被认为通过组成性地或响应诸如白细胞介素 -1α（IL -1α）或肿瘤坏死因子 -α（TNFα）等介质而产生集落刺激因子（CSF）和其他细胞因子来调节造血作用。这些炎性细胞因子诱导基质细胞中CSF表达的机制尚未完全明确。在本研究中，我们使用经猿猴病毒40转化的人骨髓基质细胞（SV - MSCs）来研究生长因子和细胞因子基因对IL -1α和TNFα的反应调节。IL -1α诱导白细胞介素 -6（IL -6）、白细胞介素 -1β（IL -1β）、粒细胞 - 巨噬细胞集落刺激因子（GM - CSF）以及程度较轻的粒细胞集落刺激因子（G - CSF）的稳态mRNA水平显著且持续升高；这种诱导不依赖于新的蛋白质合成。核转录分析表明，IL -1α转录激活IL -6、GM - CSF和IL -1β的基因，而TNFα转录诱导IL -6和IL -1β的表达。此外，白细胞介素 -6和白细胞介素 -1β的mRNA被放线菌酮和TNFα的组合显著超诱导。当SV - MSCs在半固体培养基中培养时，它们形成了 blast 样细胞集落，当重新接种到塑料培养皿上时，恢复贴壁生长。这些“集落衍生”细胞系与它们所衍生的亲代SV - MSCs不同，组成性地表达集落刺激活性以及GM - CSF、G - CSF、IL -6和IL -1β的mRNA。在本报告中，我们表明集落衍生细胞系中IL -6和IL -1βmRNA的表达至少部分归因于这些基因的组成性转录激活（类似于在IL -1α和/或TNFα刺激的亲代SV - MSCs中的发现）。然而，与细胞因子诱导的亲代SV - MSCs中GM - CSF基因的转录激活相反，GM - CSF转录本在集落衍生细胞系中通过转录后机制积累。
