Witsell A L, Schook L B
Department of Animal Sciences, University of Illinois, Urbana 61801.
Proc Natl Acad Sci U S A. 1992 May 15;89(10):4754-8. doi: 10.1073/pnas.89.10.4754.
Previous experiments have revealed the expression of tumor necrosis factor alpha (TNF-alpha) transcripts in all murine bone marrow-derived macrophage colonies isolated from days 5 through 9 of differentiation in vitro. These results implicated a role for TNF-alpha gene expression during macrophage differentiation. Antisense oligomers to the initiation region of the TNF-alpha message were used to inhibit its expression, thus allowing the role of TNF-alpha gene expression in controlling the differentiation of macrophages to be determined. Results showed that TNF-alpha regulated the proliferation of macrophages during differentiation. Cells isolated on day 3 were exclusively vulnerable to the effects of blocking TNF-alpha gene expression, displaying a 30% increase in proliferation over control cells or sense oligomer-treated cells. Thus, in the absence of TNF-alpha gene expression, cells maintained proliferation instead of undergoing terminal differentiation. Exogenous TNF-alpha was capable of rescuing day 3 antisense-treated cells, therefore maintaining normal levels of proliferation. In contrast, blocking interleukin 1 beta gene expression by antisense oligonucleotide treatment had no effect on proliferation. Addition of exogenous recombinant murine or human TNF-alpha decreased the total cell number 25-50% regardless of whether cells were grown in medium containing colony-stimulating factor 1 (CSF-1) or granulocyte-macrophage colony-stimulating factor (GM-CSF). These results suggested that exogenous TNF-alpha suppressed proliferation of early hematopoietic progenitors, whereas endogenous TNF-alpha regulated proliferation of macrophage progenitors. The number of differentiated, adherent macrophages on day 5 of differentiation in vitro was increased by TNF-alpha treatment of GM-CSF-induced macrophages but was suppressed in CSF-1-induced macrophages. These findings suggest that distinct TNF receptor expression and/or signaling is induced in differentiating macrophages stimulated with either growth factor.
先前的实验已揭示，在体外分化第5天至第9天分离得到的所有小鼠骨髓来源巨噬细胞集落中，均有肿瘤坏死因子α（TNF-α）转录本的表达。这些结果表明TNF-α基因表达在巨噬细胞分化过程中发挥作用。利用针对TNF-α信使起始区域的反义寡聚物抑制其表达，从而确定TNF-α基因表达在控制巨噬细胞分化中的作用。结果显示，TNF-α在巨噬细胞分化过程中调节其增殖。第3天分离的细胞对阻断TNF-α基因表达的作用尤为敏感，与对照细胞或正义寡聚物处理的细胞相比，其增殖增加了30%。因此，在缺乏TNF-α基因表达的情况下，细胞维持增殖而非进行终末分化。外源性TNF-α能够挽救第3天经反义处理的细胞，从而维持正常的增殖水平。相比之下，通过反义寡核苷酸处理阻断白细胞介素1β基因表达对增殖没有影响。无论细胞在含有集落刺激因子1（CSF-1）或粒细胞-巨噬细胞集落刺激因子（GM-CSF）的培养基中生长，添加外源性重组小鼠或人TNF-α均可使细胞总数减少25%-50%。这些结果表明，外源性TNF-α抑制早期造血祖细胞的增殖，而内源性TNF-α调节巨噬细胞祖细胞的增殖。对GM-CSF诱导的巨噬细胞进行TNF-α处理，可增加体外分化第5天分化的贴壁巨噬细胞数量，但对CSF-1诱导的巨噬细胞则有抑制作用。这些发现表明，在用任何一种生长因子刺激的分化巨噬细胞中，会诱导出不同的TNF受体表达和/或信号传导。
Zotero 插件